With the help of high technology, more and more substances _________ in the past years.
#101033
A
discovered
B
have discovered
C
had been discovered
D
have been discovered
推荐题目
----- Have you ever visited the 2010 Shanghai World Expo? -----Yes．When I was in China , I ______ it twice．
#103152
A
have visited
B
visited
C
had visited
D
would visit
—Could I use your dictionary?—Sorry, it __________.
#102450
A
is using
B
was using
C
was used
D
is being used
All the task __________ ahead of time, so they decided to go on holiday for a week.
#102577
A
having finished
B
had finished
C
having been finished
D
had been finished
—Tommy is planning to buy a car.—I know. By next month he _____ enough for a used one.
#100921
A
will have saved
B
saved
C
will save
D
saves
Put on your coat! I _________ you down to the doctor.
#100216
A
have been taking
B
am taking
C
took
D
have taken