World leaders have to face the fact that ________ global warming has become perhaps ________ most complicated issue.
| A．/；the | B．/；/ |
| C．the；the | D．the；/ |
The book is meant to ___needs it .
| A．who | B．whoever | C．whomever | D．whom |
The couple are spending their holiday on __is described as one of the most beautiful islands .
| A．that | B．what | C．which | D．where |
See the flag on top of the building ? That was ___ we did this morning .
A when B. which C. where D. what
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．that | C．whether | D．how |