(2012·四川)Scientists study ________ human brains work to make computers.

A．when B．how C．that D．whether

I'd like to start my own business—that's ________ I'd do if I had the money.(2011·江西)

A．why B．when C．which D．what

I'm afraid he's more of a talker than a doer，which is ________ he never finishes anything.(2011·山東)

A．that B．when C．where D．why

Part of the reason Charles Dickens loved his own novel，David Copperfield，was ________ it was rather closely modeled on his own life.(2010·北京)

A．what B．that C．why D．whether

(2010·江蘇)—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

The last time we had great fun was ________ we were visiting the Water Park.

A．where B．how C．when D．why

Engines are to machines ________ hearts are to animals.

A．as B．that C．what D．which

After three hours'climbing，they reached ________ they thought was the place they'd been dreaming of.

A．what B．which C．where D．that

A plan has been put forward ________ more graduates should go to work in the country.

A．when B．that C．whether D．how

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