Verbs and Tenses

This is correct answer because the sentence is in Simple present tense. So the verb must be in simple present tense. As Birds is plural form, verb must be singular. Hence migrate

This is the correct answer. As the given statement is in simple past tense, the verb also must be in simple past i.e. went. The word 'yesterday' is the clue that the sentence is in simple past

This is the correct answer. The word 'since' shows that the sentence is in present perfect continuous tense. So, 'has been teaching' is the present perfect continuous form of the verb 'teach'.

This is the correct answer. The word 'yet' shows that the sentence is in present perfect tense. 'Has responded' is the present perfect form of the verb 'respond'.

This is the correct answer. The word 'for' tells that the given sentence is in present perfect continuous tense. 'Has been raining' is present perfect continuous form of the verb 'rain'.

This is the correct answer. The word 'Don't disturb' shows that the sentence is in present continuous tense. 'Is doing' is the present continuous form of the verb 'do'.

This is the correct answer. To know that the given sentence is in past perfect tense, there are two clues. One is the word 'before' and the other is the presence of simple past form of other verb i.e. 'reached'. Past perfect tense always comes in the combination of 'simple past tense'. 'Had begun' is past perfect form of the verb 'began'.

This is the correct answer. The words 'at this time & tomorrow' shows that the sentence is in future continuous tense. Will be playing is the future continuous form of the verb 'play'.

This is the correct answer. The word 'next Monday' indicates that the sentence is in simple future tense. 'Will go' is the simple future form of the verb 'go'.

This is the correct answer. The word 'by' indicates that the sentence is in future perfect tense. But 'will have taken' is the future perfect form of the verb 'take'.

This is the correct answer. The word 'yesterday' tells that the sentence is in simple past tense. 'Received' is the simple past form of the verb 'receive'.

This is the correct answer. The word 'last month' tells that the given sentence is in simple past tense. 'Came' is the simple past form of the verb 'come'.

This is the correct answer. The word 'now' tells that the given sentence is in present continuous tense. 'Am writing' is the present continuous form of the verb 'write'.

This is the correct answer. The sentence is denoting the future event. Thus its tense is simple future. 'Will call' is the simple future form of the verb 'call'.

This is the correct answer. The word 'by' shows that the sentence is in future perfect tense. So the verb must also be in the same tense. 'Will have increased' is the future perfect form of the verb 'increase'.