Ii. make the following sentences (a) negative; (b) interrogative. 1. liz is trying to fix her washing machine. 2. we were having lunch when our uncle came. 3. she has already started her new job. 4. by the end of the year he had learnt to speak french. 5. my secretary has been typing the report for five hours. iii. ask all types of questions to the following sentences. 1. aunt betty is talking to the butcher in the kitchen. 2. it was raining heavily yesterday morning. 3. they hadn't completed the test when the teacher came. 4. by the end of the autumn, they will have built a new skating-rink in this dis- trict. 5. they had been watching tv for half an hour when their parents came. iv. use the correct form of the verb instead of the infinitives it brackets. 1. past simple or past progressive: my hat (to fly off) when i (to cross) the bridge. 2. past simple or present perfect: i (to buy) a new car last summer, but i (not sell) my old car yet, so now i've got two cars. 3. present simple or future perfect: the party (to begin) by the time we (to come). 4. present perfect or present perfect progressive: she (to read) this book for three days and (to read) 300 pages already. 5. past simple or past perfect progressive: how long they (to wait) for a taxi be- for it (to come)?