—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
(2013·重庆，24)John invited about 40 people to his wedding，most of ________ are family members.
A. them B．that C．which D．whom
(2013·新课标Ⅱ，4)When I arrived，Bryan took me to see the house________I would be staying.
A．what B．when C．where D．which
