In the past decades, sea ice _____in the Arctic as a result of global warming.
#102142
A
had melted
B
has been melting
C
melted
D
is melting
推荐题目
All visitors to this village______ with kindness.
#101940
A
treat
B
are treated
C
are treating
D
had been treated
  In the last few years thousands of films ________all over the word.(2011·天津)
#99051
A
have produced
B
have been produced
C
are producing
D
are being produced
 The room _______ very useful when we had visitors.
#101127
A
was proved
B
has been proved
C
has proved
D
proved