Choose the correct option to fill in the blank in the given sentence:
I will _____ the bike once we step outside.
A) Start
B) Begin
C) Commence
D) Initiate

Hint: In the given sentence, we have the subject ‘I’, the helping verb ‘will’, and the object ‘bike’ in the first clause. The clause is missing out on the main verb, i.e. the action that the subject will do on the bike. Therefore, the blank will be filled with a verb.

Complete answer:
All the words given in the options are synonyms. It means that they all mean the same thing. But they are used with different parts of speech and that is what makes them different. In the given sentence, we see that the blank is followed by ‘the bike’ which is a noun and more specifically, is machinery.

Let us analyze the given options:
Option A) Start – The word ‘start’ means to begin, but unlike ‘begin’ it is used with verbs. For e.g. When will you start eating healthy? But it also has special uses, like when we operate a machine or an organization, we use the word ‘start’. For e.g. He could not start the engine. You could start a business. Therefore, this is the correct option.
Option B) Begin – The word ‘begin’ means to perform or to undergo the first part of an action or an activity, which is generally a noun. For e.g. I cannot wait for the holidays to begin. This has a very similar meaning to start but it is not the best option. Thus, this option is incorrect.
Option C) Commence – This word also means to start or to begin something. But this word has a very formal usage. For e.g. The conference will commence in another 15 minutes. It is used for large scale organized processes. Therefore, this option is wrong.
Option D) Initiate – The word ‘initiate’ means to set something in motion and it also has a formal use. For informal usage, it is used when someone is introduced to something for the first time. For e.g. He was initiated into drug use at a very young age.

Thus, the correct answer is Option (A) i.e, I will start the bike once we step outside.

Note: In the sentence given in the question, we used the word ‘start’ as a verb. The word ‘start’ can also be used as a noun, meaning, beginning, inception, onset, etc. For e.g. We really need a good start at this particular game. The opposite or antonym of ‘start’ stops, end, finish, etc.