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
After three hours'climbing，they reached ________ they thought was the place they'd been dreaming of.
A．what B．which C．where D．that
Engines are to machines ________ hearts are to animals.
A．as B．that C．what D．which
The last time we had great fun was ________ we were visiting the Water Park.
A．where B．how C．when D．why
(2010·江苏)—I prefer shutting myself in and listening to music all day on Sundays.
—That's ________ I don't agree.You should have a more active life.
A．where B．how C．when D．what
