I can’t quite remember ___ you started doing the work.
| A．that is was when | B．when it was that | C．when was it that | D．that was it when |
There are some health problems that, when ________ in time, can become bigger.
| A．not treated | B．not being treated |
| C．not to be treated | D．not having been treated |
In the global economy, a new drug for cancer, ________ it is discovered, will create many economic possibilities around the world.
| A．whatever | B．whoever |
| C．wherever | D．whichever |
Don't turn off the computer before closing all programs, ________ you could have problems.
| A．or | B．and |
| C．but | D．so |
I was glad to meet Jenny again, ______ I didn't want to spend all day with her.
| A．but | B．and |
| C．so | D．or |
（2013·北京卷)Many countries are now setting up national parks animals and plants can be protected.
| A．when | B．which | C．whose | D．where |