I just don’t understand ____that leads to so many teenagers becoming addicted to playing computer games.
| A．why it does | B．what it does |
| C．what it is | D．why it is |
I admire my English teacher. I can remember very few occasions ________ she stopped working because of ill health.
| A．that | B．when | C．where | D．which |
—Did you know more about the mine accident?
—Oh，sorry，I had no idea. I ________ the Rescue Center now.
| A．will be phoning | B．am to phone |
| C．will phone | D．phone |
—________ you interrupt now? Can't you see I'm on the phone?
—Sorry Sir, but it's urgent.
| A．Can | B．Should | C．Would | D．Must |
As is reported, it will be more than 20 years ________ humans are able to walk on Mars.
| A．before | B．when | C．since | D．after |
Be careful that a good name of a product doesn't ________ mean good quality of it.
| A．alternatively | B．approximately |
| C．obviously | D．necessarily |