diff --git a/src/constants.ts b/src/constants.ts
index a642b6c1..a7dafa12 100644
--- a/src/constants.ts
+++ b/src/constants.ts
@@ -33,7 +33,8 @@ export const ALIASES = Object.freeze({
 	wed: 3,
 	thu: 4,
 	fri: 5,
-	sat: 6
+	sat: 6,
+	l: 'l'
 } as const);
 export const TIME_UNITS_MAP = Object.freeze({
 	SECOND: 'second',
@@ -65,3 +66,5 @@ export const PRESETS = Object.freeze({
 } as const);
 export const RE_WILDCARDS = /\*/g;
 export const RE_RANGE = /^(\d+)(?:-(\d+))?(?:\/(\d+))?$/g;
+export const RE_QUESTIONMARK = /\?/g;
+export const RE_L = /[lL]/g;
diff --git a/src/time.ts b/src/time.ts
index 488602e6..c9a80d20 100644
--- a/src/time.ts
+++ b/src/time.ts
@@ -5,6 +5,8 @@ import {
 	CONSTRAINTS,
 	PARSE_DEFAULTS,
 	PRESETS,
+	RE_L,
+	RE_QUESTIONMARK,
 	RE_RANGE,
 	RE_WILDCARDS,
 	TIME_UNITS,
@@ -671,6 +673,9 @@ export class CronTime {
 			throw new CronError('Too many fields');
 		}
 
+		//timestamp for eventual '?' substitution
+		const now = DateTime.local();
+
 		const unitsLen = units.length;
 		for (const unit of TIME_UNITS) {
 			const i = TIME_UNITS.indexOf(unit);
@@ -679,7 +684,7 @@ export class CronTime {
 			// This adds support for 5-digit standard cron syntax
 			const cur =
 				units[i - (TIME_UNITS_LEN - unitsLen)] ?? PARSE_DEFAULTS[unit];
-			this._parseField(cur, unit);
+			this._parseField(cur, unit, now);
 		}
 	}
 
@@ -694,7 +699,7 @@ export class CronTime {
 	 *   - Starting with the lower bounds of the range iterate by step up to the upper bounds and toggle the CronTime field value flag on.
 	 */
 
-	private _parseField(value: string, unit: TimeUnit) {
+	private _parseField(value: string, unit: TimeUnit, now: DateTime) {
 		const typeObj = this[unit] as TimeUnitField<typeof unit>;
 		let pointer: Ranges[typeof unit];
 
@@ -712,6 +717,12 @@ export class CronTime {
 			}
 		});
 
+		// "L" is a shortcut for the last day of the month
+		value = value.replace(RE_L, this._getLastDayOf(now, unit));
+
+		// "?" will be replaced with current timestamp value
+		value = value.replace(RE_QUESTIONMARK, this._getTimeUnit(now, unit));
+
 		// "*" is a shortcut to [low-high] range for the field
 		value = value.replace(RE_WILDCARDS, `${low}-${high}`);
 
@@ -776,4 +787,28 @@ export class CronTime {
 			}
 		}
 	}
+
+	private _getTimeUnit(now: DateTime, unit: TimeUnit) {
+		switch (unit) {
+			case 'second':
+				return now.second.toString();
+			case 'minute':
+				return now.minute.toString();
+			case 'hour':
+				return now.hour.toString();
+			case 'dayOfMonth':
+				return now.day.toString();
+			case 'month':
+				return now.month.toString();
+			case 'dayOfWeek':
+				return this._getWeekDay(now).toString();
+			default:
+				throw new CronError('Invalid time unit');
+		}
+	}
+
+	private _getLastDayOf(now: DateTime, unit: TimeUnit) {
+		if (unit === 'dayOfMonth') return now.endOf('month').day.toString();
+		return '7';
+	}
 }
diff --git a/tests/crontime.test.ts b/tests/crontime.test.ts
index 8d9d2426..839de341 100644
--- a/tests/crontime.test.ts
+++ b/tests/crontime.test.ts
@@ -352,20 +352,6 @@ describe('crontime', () => {
 		});
 	});
 
-	describe('should throw an exception because `L` not supported', () => {
-		it('(* * * L * *)', () => {
-			expect(() => {
-				new CronTime('* * * L * *');
-			}).toThrow();
-		});
-
-		it('(* * * * * L)', () => {
-			expect(() => {
-				new CronTime('* * * * * L');
-			}).toThrow();
-		});
-	});
-
 	it('should strip off millisecond', () => {
 		const cronTime = new CronTime('0 */10 * * * *');
 		const x = cronTime.getNextDateFrom(new Date('2018-08-10T02:20:00.999Z'));
@@ -777,4 +763,95 @@ describe('crontime', () => {
 			new CronTime('* * * * *', 'Asia/Amman', 120);
 		}).toThrow();
 	});
+
+	describe('should support question mark', () => {
+		it('should substitute minute', () => {
+			const clock = sinon.useFakeTimers();
+
+			const now = DateTime.local();
+			const ct = new CronTime('? * * * *');
+			const minutes = ct.sendAt().get('minute');
+			expect(minutes).toBe(now.get('minute'));
+
+			clock.restore();
+		});
+
+		it('should substitute seconds', () => {
+			const clock = sinon.useFakeTimers();
+
+			const now = DateTime.local();
+			const ct = new CronTime('? * * * * *');
+			const second = ct.sendAt().get('second');
+			expect(second).toBe(now.get('second'));
+
+			clock.restore();
+		});
+
+		it('should substitute hours', () => {
+			const clock = sinon.useFakeTimers();
+
+			const now = DateTime.local();
+			const ct = new CronTime('* ? * * *');
+			const hour = ct.sendAt().get('hour');
+			expect(hour).toBe(now.get('hour'));
+
+			clock.restore();
+		});
+
+		it('should substitute day', () => {
+			const clock = sinon.useFakeTimers();
+
+			const now = DateTime.local();
+			const ct = new CronTime('* * ? * *');
+			const day = ct.sendAt().get('day');
+			expect(day).toBe(now.get('day'));
+
+			clock.restore();
+		});
+
+		it('should substitute month', () => {
+			const clock = sinon.useFakeTimers();
+
+			const now = DateTime.local();
+			const ct = new CronTime('* * * ? *');
+			const month = ct.sendAt().get('month');
+			expect(month).toBe(now.get('month'));
+
+			clock.restore();
+		});
+
+		it('should substitute dayOfWeek', () => {
+			const clock = sinon.useFakeTimers();
+
+			const now = DateTime.local();
+			const ct = new CronTime('* * * * ?');
+			const month = ct.sendAt().get('weekday');
+			expect(month).toBe(now.get('weekday'));
+
+			clock.restore();
+		});
+	});
+
+	describe("should support 'L' for last day of the month", () => {
+		it('should substitute last day of the month for "* * L * *"', () => {
+			const clock = sinon.useFakeTimers();
+
+			const now = DateTime.local();
+			const ct = new CronTime('* * L * *');
+			const day = ct.sendAt().get('day');
+			expect(day).toBe(now.endOf('month').get('day'));
+
+			clock.restore();
+		});
+
+		it('should substitute last day of the week for "* * * * * L', () => {
+			const clock = sinon.useFakeTimers();
+
+			const ct = new CronTime('* * * * L');
+			const day = ct.sendAt().get('weekday');
+			expect(day).toBe(7);
+
+			clock.restore();
+		});
+	});
 });