. If _____ to look after luggage for someone else, inform the police at once.
| A．asked | B．to ask | C．asking | D．having asked |
Which of the following is wrong? _________
| A．They didn't find the secret until they got home. |
| B．Not until they got home did they find the secret. |
| C．It was not until they got home that they found the secret. |
| D．Not until did they get home that they found the secret. |
—Shall we go for a walk rather than watch television?
— _________. Whatever you want to do is fine with me.
| A．It just depends | B．Let's get going |
| C．It's up to you | D．That's all right |
Robert has _________ the good habit of making notes.
| A．grew | B．developed |
| C．made | D．Invented |
You can't imagine what great fun my brother and I had _________ up and down the tall, shaky steps.
| A．walk | B．to walk |
| C．walking | D．Walked |
—I find the environment is getting worse and worse. —Yes, that is _________ we humans go against nature.
| A．Because | B．why |
| C．that | D．How |