— The woman biologist stayed in Africa studying wild animals for 13 years before she returned.
— Oh, dear ! She ______ a lot of difficulties !
| A．may go through | B．might go through |
| C．ought to have gone through | D．must have gone through |
He had to sell his luxury car, ________ his company was in debt.
| A．before | B．until |
| C．while | D．for |
Jane had just finished her homework ________ her mom asked her to practice playing the violin yesterday.
| A．when | B．while |
| C．after | D．before |
Just be patient．You _____ expect the world to change so soon．
| A．can’t | B．may not |
| C．needn’t | D．didn’t |
Having finished the work，__________．
| A．it was almost six o’clock |
| B．supper was ready |
| C．a postman came and delivered some letters． |
| D．we had a rest and then had supper |
It was with great joy _______ Tom received the news that his lost son had been found．
| A．because | B．which |
| C．since | D．that |