. It is pretty well understood ________ controls the flow of carbon dioxide in and out the atmosphere today.
| A．that | B．that what | C．what | D．how |
You can take any seat _____is free .
| A．where | B．which | C．that | D．in which |
They have to work on Sundays,_____they don’t like .
| A．but | B．so | C．that | D．which |
The most important thing ______they need is more time .
| A．what | B．that | C．which | D．in which |
I lived in Beijing,_____is the capital of China.
| A．which | B．where | C．that | D．what |
After five hours’ drive ,they reached _____they thought was the place their parents had lived many years ago .
| A．that | B．where | C．which | D．what |