The warning we were given as children ________ an apple a day keeps the doctor away may，in fact，have a scientific explanation.
A．that B．who C．where D．which
WalMart，the world's largest retailer(零售商)，sells in three months ________ the numbertwo retailer Home Depot sells in a year.
A．that B．which C．when D．what
Professor Tang didn't give us a speech today.It was ________ he had a traffic accident on the way to school.
A．that B．when C．why D．because
He taught his father how to get to know ________ is going on in his university life on the Internet.
A．how B．that C．what D．which
It is obvious ________ the former Libyan government will be replaced with the opposition government.
A．who B．where C．which D．that
When we arrived in ________ used to be called the foggy capital，we found London completely changed.London is now one of the capital cities in the world with the finest air quality.
A．which B．what C．that D．where
