Half of the books ________easy for the students to read.  
#44200
A
are
B
is
C
am
D
be
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 Every possible means ______ to prevent the air pollution, but the sky is still not clear. 
#85598
A
has been used 
B
have been used
C
is used 
D
are used
Tina used to __________a round face. 
#44065
A
is
B
have
C
be
D
has
A library together with 5000 books  for the school.
#86091
A
was provided
B
were provided
C
provided
D
have provided