Mountain climbing ______ be really dangerous at times even though it is challenging and exciting in general.
| A．can | B．should | C．shall | D．must |
You _____be careful with the camera. It costs!
| A．must | B．may | C．can | D．will |
That restaurant is extremely popular, ______ you may have to wait to get a seat.
| A．for | B．so |
| C．or | D．yet |
It is so cold that you can’t go outside _____ fully covered in thick clothes.
| A．if | B．unless |
| C．once | D．when |
As you go through this book, you ________ that each of the millions of people who lived through World War II had a different experience.
| A．will find | B．found |
| C．had found | D．have found |
It was when we were returning home ________ I realized what a good feeling it was to have helped someone in trouble.
| A．which | B．that |
| C．where | D．how |