我国争取到2020年,全社会研究开发投入占国内生产总值的比重提高到()以上。
A.2%
B.3%
C.2.50%
D.4%
参考答案:C
Though it was the first time that I ______ the small town, I fell in love with it at once.
A.was visiting
B.visit
C.have visited
D.had visited
下列生物活性物质不属于内分泌的是().
A.甲状腺素
B.肾上腺素
C.前列腺素
D.胰岛素
E.内因子