Question

We
(spend) a great deal on phone calls due to postal strike.

will spend
spent
will have been spent
will be spent​

Answer 1

Explanation:

The most appropriate option here seems to be "spent", for following reasons

• Will spend is not suitable because "will" describes something to be done in future but as the reason is already mentioned, it shows that something has already happened

• Will have been spent is also not right because there is no time specified here

• Will be spent is wrong because "will be" can not combined with spent, it should be "spending" instead.

Answer 2

The most appropriate option to be filled in the blank is the option 'spent'

We  spent a great deal on phone calls due to postal strike.

(Action happened in the past)

The second most appropriate option is 'will spend'

We  will spend a great deal on phone calls due to postal strike.

(Action may happen in future)

Explanation

The first sentence describes action in the past and second sentence is about future.