69. The performance (begin).at 7 oclock and (last) for 3 hours. 70. You (be).here before? - Yes, I (spend) my holidays here last year. 71. He (leave)for London 2 years ago and I (not see) him since. 72. You (be)to the laboratory this week? 73. Thousands of people (see) this exhibition by the end of the month. 74. By the time you (finish). cooking they (do) their homework. 75. I dont think he (change)in the thirty years I (know) him. 76. Then about a year ago he (disappear).and I (never hear) from him since. 90. He no sooner (reach) the door than he (come).back. 91. He (have) a bad fall while he (repair)his roof. 92. By the end of this month, I hope, I (write)200 pages of my new novel. 93. It (take).a moment before Nick (realize) he (offer) a cigarette by the stranger. 94. While he ( learn). to drive he (have) 25 accidents. 95. Its no using getting inpatient. The plane (not arrive) until the weather (clear)up. 96. I (think) about you a lot lately and I (come) to the conclusion that I( not be) able to live without you. 97. I dont mind ( wait)Id rather (be).too early than too late. 98. Those students who (fail)the exam are going to take another one held in August. 99. I am just going out to get an evening paper. But it (rain).Why you (not wait) till the rain (stop)? 100. I (think) your fathers health (improve)so much since I (see)him last Cần giải chi tiết ạ.