A.the development of new ideas
B.his basic research
C.his manipulation of genes
D.the consequences of his discoveries

A.serious environmental pollution
B.activities of an overpopulated society's industry
C.activities of surplus human population
D.the waste products dumped into our environment

A.The workers at the factory shouldn’t wear protective clothing.
B.The workers at the factory must wear protective clothing.
C.The workers at the factory needn’t wear protective clothing.
D.The workers at the factory may wear protective clothing.

A.about
B.on
C.for
D.at

A.participate
B.to participating
C.participating
D.to participate

A.result in
B.hold on
C.take over
D.keep to

A.is he
B.does he
C.isn't he
D.doesn't he

A.knowledgeably
B.knowledgeable
C.knowledge
D.know

A.light-hearted
B.big-hearted
C.warm-hearted
D.whole-hearted

A.As soon as it stops raining
B.After it had stopped raining
C.When it stopped rainingD. Once it stopped raining
D.