A new kind of drug ___ ___ to cure H7N9 bird flu by the scientists and they are hopeful that they will succeed in a couple of weeks.
A.has been developed | B.is being developed | C.is developing | D.has developed |
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A new kind of drug ___ ___ to cure H7N9 bird flu by the scientists and they are hopeful that they will succeed in a couple of weeks.
A.has been developed | B.is being developed | C.is developing | D.has developed |