Question

Fill in the blank with the most appropriate word.
Long ago, people thought that the earth was flat. Long ago, the earth _____ flat.
a) was thinking to be
b) was thought to be
c) is thought to be
d) thought to be

Answer 1

Hint: The first sentence already tells us the required tense. If you rearrange these words in the correct way and add an infinitive, the phrase will be correct to use in the second sentence.

Complete answer:
 We can discern whether the actions are happening
right now by certain pointers that are given in the sentence in the question. So, let us deconstruct the given sentence.
In the first part, the verbs used are ‘thought’ and ‘was’, i.e. they are simple past tense verbs. This means that the action has ended. So, naturally, in the second part as well, the action will be finished.

However, the structure is different. One sentence is in the active voice, and the other is in the passive voice. The second sentence is passive.
So, the construction should be verb + verb + infinitive.

Now, we know what we are looking for. Let’s look at the given options:

a) was thinking to be - This tense is a past continuous construction, as there is a verb with the ending ‘-ing’. This is not the verb that fits into the blank, as it is a different construction. This is not the required answer. So, this is an incorrect option.
b) was thought to be - This tense is a simple past tense construction. It uses the same verb forms as the complete sentence in the question, so it fits. This is the required answer. So, this is the correct option.
c) is thought to be - This tense is a simple present tense construction. This is not the verb that fits into the blank, as it is a different construction. This is not the required answer. So, this is an incorrect option.
d) thought to be - This construction is missing a helping verb. This means that this phrase is grammatically incorrect. This is not the required answer. So, this is an incorrect option.

Note:
Try to look for certain pointer words. They will help you understand which option you are looking for. Then, go through the given options, and choose the most appropriate option accordingly.