Barrack Obama __________ President of the United States since 2010.
#63757
A
became a
B
has become a
C
has turned
D
has been
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 Up to now, our society ________ with limited living space and a shortage of natural resources.
#63760
A
has been challenged
B
is being challenged
C
is challenging
D
has challenged
Because of the bad weather, my mother ____ and lay in bed. She ______ for a week. 
#63793
A
has been ill; was ill
B
fell ill; has fallen ill
C
fell ill; has been ill
D
fell ill; is ill
Barrack Obama __________ President of the United States since 2010.
#63757
A
became a
B
has become a
C
has turned
D
has been
 Kate  ________    on her new novel, which is supposed to come out next month.
#63761
A
was working
B
had worked
C
will be working
D
has been working