1 Dairy farming is _____ leading agricultural activity in the Unites States.
(A) a
(B) at
(C) then
(D) none
A.
 
2 Although thunder and lightning are produced at the same time, light waves travel faster ____, so we see the lightning before we hear the under.
(A) than sound waves do
(B) than sound waves are
(C) do sound waves
(D) sound waves
A.
 
3 Beef cattle ____ of all livestock for economic growth in certain geographic regions.
(A) the most are important
(B) are the most important
(C) the most important are
(D) that are the most important
B.
 
4 The discovery of the halftone process in photography in 1881 made it ____ photographs in books and newspapers.
(A) the possible reproduction
(B) possible to reproduce
(C) the possibility of reproducing
(D) possibly reproduced
B.
 
5 Flag Day is a legal holiday only in the state of Pennsylvania, ____ Betsy Ross sewed the first American flag.
(A) which
(B) where
(C) that
(D) has
B.
 
6 ____ vastness of the Grand Canyon, it is difficult to capture it in a single photograph.
(A) While the
(B) The
(C) For the
(D) Because of the
D.
 
7 Speciation , ___ , results when an animal population becomes isolated by some factor, usually geographic.
(A) form biological species
(B) biological species are formed
(C) which forming biological species
(D) the formation of biological species
D.
 
8 In this pure state antimony has no important uses, but ___ with other substances, it is an extremely useful metal.
(A) When combined physically or chemically
(B) combined when physically or chemically
(C) the physical and chemical combination
(D) it is combined physically and chemically
A.
 
9 The dawn redwood appears _____ some 100 million years ago in northern forests around the world.
(A) was flourished
(B) having to flourish
(C) to have flourished
(D) have flourished
C.
 
10 Beginning in the Middle Ages, composers of Western music used a system of notating their compositions _____ be performed by musicians.
(A) will
(B) that
(C) and when to
(D) so they could
D.
 
11 Civil Rights are the freedoms and rights ____ as a member of a community, state or nation.
(A) may have person
(B) may have a person who
(C) a person may have
(D) and a person may have
C.
 
12 Richard Wright enjoyed success and influence ____ among Black American writers if his
era.
(A) were unparalleled
(B) are unparalleled
(C) unparalleled
(D) the unparalleled
C.
 
13 ____ of large mammals once dominated the North American prairies the American bison
and the pronghorn antelope.
(A) There are two species
(B) With two species
(C) Two species are
(D) Two species
D.
 
14 Franklin D. Roosewelt was ____ the great force of radio and the opportunity it provided for
taking government policies directly to the people.
(A) as the first President he understood fully
(B) the first president that to fully understand
(C) the first President fully understood
(D) the first President to understand fully
D.
 
15 During the late fifteenth century ____ of the native societies of America had professions in the fields of arts and crafts.
(A) only a few
(B) a few but
(C) few, but only
(D) a few only
A.

16 The firstly naval battle of the Revolutionary War was fought off the coast
A B C
of Machias, Maine in June, 1775.
D
A.
firstly →first 。
 
17 The public ceremonies of the Plains Indians are lesser elaborate than those of the Navajo,
A B C
in the Southwest.
D
B.
lesser →less 。
 
18 In some species of fish, such the three-spined stickleback, the male, not the female,
A B
performs the task of caring for the young.
C D
B.
such the →such as the 。
 
19 When