Question

When they looked (A) through the window. (B) they see a boy (C) hiding behind a tree (D).​

Answer 1

Answer:

C

Explanation:

the correct one

When they looked will be through the windowthey saw a boyhiding behind a tree

Answer 2

Answer:

When they looked through the window they saw a boy hiding behind a tree.

There is an error in the mentioned sentence and it is related to tense.

Explanation:

• It is obvious that the event in the sentence has already happened and finished in the past.
• As we know, the simple past is a tense that is used to talk about things that took place or existed before present time.
• Example: She waited for him at the airport.
• Also, the past participle (looked) is already representing that the sentence is in simple past tense.
• Therefore, use of first form of verb (see) is inaccurate and it must be replaced by second form of verb 'saw' to make the sentence error-free.

Hence, the erroneous part is, 'they see a boy'.