. Sales of CDs have greatly increased since the early 1990s, when people ________ to enjoy the advantages of this new technology.
#104797
A
begin
B
began
C
have begun
D
had begun
推荐题目
--Do you want to see Ice Age 4 tonight? -- I ________ the movie already. It is very funny!
#100145
A
see
B
saw
C
have seen
D
will see
—Got your driving license?—No. I ____ too busy to have enough practice, so I didn’t take the driving test last week.
#104518
A
was
B
am
C
have been
D
had been
A high-tech exhibition ________in the National Museum now. Let’s go and visit it.
#100890
A
will be held
B
is being held
C
was held
D
has been held
Nearly half a million immigrants，many of them English—speaking， in the country during the last quarter of the nineteenth century．
#102171
A
have arrived
B
had arrived
C
arrived
D
have been arriving
By the time Billy was 6, he in the sea.
#101498
A
had already swum
B
was already swimming
C
has already swum
D
already swam