20. When Jack arrived, he learned Mary ____ for almost an hour.
| A．had gone | B．had set off | C．had left | D．had been away |
I broke my relationship with John because he always found_______ with whatever I did．
| A．error | B．mistake | C．fault | D．failure |
Without proper lessons, you could ________a lot of bad habits when playing the piano．
| A．break up | B．pick up | C．catch up | D．give up |
There are so many tall trees in the forest,______________.
| A．some of them measures over 50 meters | B．some of which measuring over 50 meters |
| C．some of them measuring over 50 meters | D．some of which measures over 50 meters |
--- I don’t know whether I should go abroad or not, Mum．
--- I leave_______ to your own judgment whether you should do it．
| A．that | B．it | C．this | D．what |
Many a woman______ important positions in society, which________impossible in the past．
| A．holds; was | B．hold ; were | C．held; was | D．holding; were |