20.If knowledge is power, ______ Sir Francis Bacon wrote in 1579, ______ perhaps creativity can be described as the ability to use that power.
A.what; and B.as; then C.which; and D.that; then
19.The WenChuan earthquake in 2008 is believed ______ more than 70,000 people and made thousands homeless, ______ it perhaps the most destroying tsunami in history.
A.to kill; making B.to have killed; making
C.having killed; to make D.killing; made
18._____ I can’t understand was _____ there are more and more junk-emails on the Internet.
A.What; why B.That; what C.What; because D.Why; that