Fill in the blank with the correct verb form.
By 2040, scientists ______ a solution to global warming. (find)

 By 2040, scientists will have found a solution to global warming.

Identify the tense of the sentence.
She had been practicing piano for three hours before the concert started.

Past perfect continuous tense.

Rearrange the words to form a meaningful sentence in the future perfect tense.
finished / their work / will / they / have / tomorrow / by

They will have finished their work by tomorrow.

True or False: The sentence "She is cooking dinner when he arrived" is grammatically correct.

False. Correct sentence: "She was cooking dinner when he arrived."

Fill in the blank with the correct verb form.
By the time we got to the station, the train ______. (leave)

 By the time we got to the station, the train had left.

Choose the correct sentence. 
(a) He has been waiting for the bus since two hours. 
(b) He has been waiting for the bus for two hours. 
(c) He had been waited for the bus for two hours.

(B) He has been waiting for the bus for two hours.

Find the mistake and correct it.
When I will arrive at the airport, I will call you.

Correction: When I arrive at the airport, I will call you.

Rearrange the words to form a meaningful sentence in the past perfect tense.
met / they / before / each other / had / the event

They had met each other before the event.

Identify the tense of the sentence.
By next year, she will have been teaching at the university for ten years.

Future perfect continuous tense.

Choose the correct sentence.
(a) She was sleeping when the phone rang. 
(b) She was sleeping when the phone rings. 
(c) She was sleeping when the phone had rang.

(A) She was sleeping when the phone rang.

Find the error in the sentence.
I am believing that he will come soon.

Correction: I believe that he will come soon.

True or False: The sentence "I was reading a book when she called me" is in the past continuous tense.

True

Choose the correct transformation of the sentence into future perfect tense. She completes her homework by 9 PM. 
(a) She will complete her homework by 9 PM. 
(b) She will have completed her homework by 9 PM. 
(c) She will be completing her homework by 9 PM.

(b) She will have completed her homework by 9 PM.

Fill in the blank with the correct verb form.
At this time tomorrow, we ______ in the exam hall. (sit)

At this time tomorrow, we will be sitting in the exam hall.

Rearrange the words to form a meaningful sentence in the present perfect continuous tense. 
she / been / working / for / this company / has / five years

She has been working for this company for five years.