31. Lewis was much admired ______ his work on the advanced medical research.
| A．on | B．in | C．for | D．With |
________ made the school proud was ________ more than 90% of the students had been admitted to key universities.
| A．What；because | B．What；that |
| C．That；what | D．That；because |
—You can't imagine ________ fantastic fun online chatting is.
—Really？But it may cause a lot of trouble sometimes.
| A．what A | B．how | C．why | D．so |
It is pretty well understood ________ controls the flow of carbon dioxide in and out the atmosphere today.
| A．that | B．when | C．what | D．how |
A plan has been put forward ________ more graduates should go to work in the country.
| A．when B | B．that | C．whether | D．how |
After three hours'climbing，they reached ________ they thought was the place they'd been dreaming of.
| A．what | B．which | C．where | D．that |