It worries the couple a lot ______ their only son is behaving worse and worse these days.
| A．how | B．why | C．that | D．what |
The head of the company promised to deal with matters of this sort _____he returned to his office．
| A．until | B．while | C．by the time | D．the moment |
The disk ,digitally ______in the studio, sounded fantastic at the party that night．
| A．recorded | B．recording | C．to be recorded | D．having recorded |
Scientists are convinced _____the positive effect of laughter _____physical and mental health．
| A．of ;at | B．by; in | C．of ; on | D．on ;at |
We had wanted to finish our task by noon, but it didn’t quite ______．
| A．find out | B．give out | C．hand out | D．work out |
____you eat the correct foods _____be able to keep fit and stay healthy．
| A．Only if ; will you | B．Only if ;you will |
| C．Unless ; will you | D．Unless ; you will |