Every means______tried but with no end.
A: have been
B: have had
C: has been
D: are
A: have been
B: have had
C: has been
D: are
举一反三
- All possible means ，but not a means an obvious effect。 A: have been tried; has B: have tried; has C: has been tried; have D: have been tried; have
- Every means ______ tried, but in vain. A: have been B: has been C: are D: is
- All possible means __________ been tired.Every possible means __________ been tired. A: have，has B: has，has C: have，have D: has，have
- Every possible means ______. A: has tried B: has been tried C: was tried D: were tried
- Scientists think that there _____ life on Earth for millions of years. A: has had B: have had C: has been D: have been