The problem was very difficult to handle．We worked it out，__________ ．
| A．too | B．yet | C．although | D．though |
---Sorry, Professor Smith. I didn’t finish the assignment yesterday.
---Oh, you___________ have done it as yesterday was the deadline.
| A．must | B．mustn’t | C．should | D．shouldn’t |
Every few years, the coal workers ___________ their lungs X-rayed to ensure their health.
| A．are having | B．have | C．have had | D．had had |
If our parents do everything for us children, we won’t learn to depend on___________
| A．themselves | B．them | C．us | D．ourselves |
Sean has formed the habit of joggingthe tree-lined avenue for two hours every day.
| A． | between | B． | along | C． | below | D． | with |
That is the only way we can imaginethe overuse of water in students' bathrooms.
| A． | reducing | B． | to reduce | C． | reduced | D． | reduce |