Scientists have spent years______ into the effects of certain chemicals on the human brain
A.studying
B.investigating
C.researching
D.inspecting
A.studying
B.investigating
C.researching
D.inspecting
第1题
Scientists have known the reason that people grow old.
A.Right
B.Wrong
C.Not mentioned
第2题
Many scientists have been probing psychological problems.
A.solving
B.exploring
C.settling
D.handling
第3题
Some scientists believe that dolphins have a language of their own
A.Right
B.Wrong
C.Not mentioned
第4题
A.active
B.resistant
C.tough
D.gradual
第6题
Scientists have found that listening to "sad" music can make one feel warmer.
A.Y
B.N
C.NG
第7题
A) is; have B) is; has C) are; have D) is; are
第8题
Scientists in Brazil have used frog skin to
A.eliminate bacteria.
B.treat burns.
C.speed up recovery.
D.reduce treatment cost.
第9题
Scientists have worked out a way to help people live longer,
A.Right
B.Wrong
C.Not mentioned