He’s got himself into a dangerous situation ________ he is likely to lose control over the plane.
A. where            B. which           C. while                D why

The reason ________ he explained was________ he was ill and unable to go to school.

---How long do you think it is ______he took up the job?
--- Half a year at least.

        you make a promise,you should keep it.

I think you could complain, _______, of course, you are happy with the way things are.

Staff are allowed to take a ten-minute break every two hours to relax, use the bathroom or do ___________ else is necessary.  

Bungee jumping is an exciting activity, very popular among young adults, ___________ courage matters more than strength. 

Remember when you learned to water ski, David?  _________ you skied more, you got better and better. It’s the same with language study. 

—Did your father phone you shortly after the accident?
—No, it was a fortnight ________ he gave me a phone call.

John’s success has nothing to do with good luck. It is years of hard work _______has made him a great scientist today.