Question

She left London,.....,......, The 4th of march

Answer 1

Explanation:

she left london on the 4th of marrch

Answer 2

This blank can be filled with the word 'on'.

So, correct sentence will be:-

She left London on the 4th of March.

On is used here because specific time is given.

There are so many other prepositions. But those prepositions can not be used here because it will not give the correct sense of the sentence.

We can define proposition as:

Prepositions are those words which are used before a noun or pronoun and denote the relation between the noun/pronoun and other parts of sentences.