29 They had finished work before leaving the office
30 We've been learning English for 5 years
31 How much does this computer cost?
32 Joe hasn't heard from his family since June
33 When did you start living in this new house?
34 I have visited Ho Chi Minh city twice before
35 If Jack had a car, he would drive to work
36 If it hadn't been for the heavy traffic, we wouldn't have been late
37 If I were you, I would ask your teacher for advice
38 Unless you tell the truth, I'll never see you again
39 James is the one who helped me solve that problem
40 The tea is too hot for me to drink
