I saw Samuel/Sam ..... the house.

Here is the answer to question 15:

15. The verb "saw" is a verb of perception. After verbs of perception (like see, hear, watch, feel), we can use either:

    • The bare infinitive (verb without "to") to describe a complete action. For example, "I saw Samuel enter the house" means I saw the entire action of him going in.
    • The present participle (-ing form) to describe an action in progress. For example, "I saw Samuel entering the house" means I saw him in the middle of the action of going in.

    Both "entering" (A) and "enter" (B) are grammatically correct options in this context. However, "entering" is often used to emphasize that the action was ongoing at the moment of observation. Options C ("was enter") and D ("was entering") are grammatically incorrect in this direct structure following "I saw Samuel/Sam."

    Given that both A and B are grammatically sound, and "entering" is a very common and natural way to describe an action observed in progress, it is a strong choice.

    The completed sentence is: "I saw Samuel/Sam entering the house."

    The answer is A.