I don’t know who sent the gift, but I’ll make a careful _________.
| A．investment | B．challenge | C．enquiry | D．guide |
the project as planned, we’ll have to work two more hours a day.
| A．To complete | B．Complete | C．Completing | D．Completed |
You don’t need to make fancy foods to impress guests—it is something simple but good _____ will do.
| A．what | B．that | C．which | D．who |
The school has developed an online systemstudents can choose their own teachers.
| A．which | B．that | C．whom | D．where |
We’d better stay here a little longerhe turns up unexpectedly.
| A．although | B．in case | C．since | D．if only |
---I’m sorry, but there is no smoking on this flight.
---Oh, I _____that. Sorry, I won’t again.
| A．don’t know | B．didn’t know | C．won’t know | D．haven’t known |