1.Drinking water _______ excessive enamel of teeth to become

1.Drinking water _______ excessive enamel of teeth to become brittle and to chip off,leaving a stained or mottled effect.
(A) containing
(B) in which containing
(C) contains
(D) that is contained
2.Carbohydrates,_______ of the three principal constituents of food,form the bulk of the average human diet
(A) are one
(B) one that
(C) one
(D) which one
3._______ the eye,a camera takes in rays of light that are reflected from an object and focuses the rays into an image.
(A) Alike
(B) As like
(C) Is like
(D) Like
4.Great pain and swelling characterize both sprains and fractures,but _______ he affected part and unnatural ting often indicate a bone
break.inability lo move
(A) inability to move
(B) they were unable to move
(C) unable to move
(D) when inability to move
5.The human skin forms _______ against the action of physical,chemical,and bacterial agents on the deeper tissues.
(A) a protective barrier is
(B) a protective barrier
(C) a barrier and protective
(D) when a protective barrier
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6.The technique of frying food has prepare n^eats,fish,vegetables,and breads.
(A) to have most cultures
(B) that in most cultures
(C) in cultures when
(D) in most cultures
7.Music has been called both the most mathematical _______ the most abstract of the arts.
(A) but
(B) and
(C) however
(D) or
8.Roots of plants lend to grow downward into soil,unless _______ more readily available at the surface.
(A) have water
(B) water has
(C) is water
(D) water is
9.United States income taxes are paid to the Internal Revenue Service,_______ funds for use by the government.
(A) which distributes
(B) and distributes
(C) the distribution of
(D) so that the distribution of
10.Robert Penn Warren's first novel was published in 1939,and seven years later,his third novel,All the King's Men,made _______
famous.
(A) he was
(B) him
(C) his
(D) how he was
11.Although legend has it that the Pilgrims first set foot in America on Plymouth Rock in 1620,_______documentary evidence confirming
(A) no
(B) still is no
(C) there is no
(D) but no
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12.The gardenia,about 200 species _______ to tropical and subtropical countries,was named in honor of eighteenth-century naturalist
Alexander Garden.
(A) native of which are
(B) are native of which
(C) which are native of
(D) of which are native
13- High-speed photography has made _______ certain aspects of motion never before seen.
(A) visible
(B) they are visible
(C) visibly
(D) it visible
14.Nitroglycerin is an unstable chemical compound that is very sensitive sudden movement _______ dangerous to transport
(A) because
(B) and therefore
(C) why it is
(D) making
15.A computer is a fast electronic machine _______ information according to a stored sequence of instructions called a program.
(A) processes
(B) that processes
(C) that it processes
(D) that processes it

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实话,有点难啊~
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