血浆药物浓度下降一半所需的时间是（）。

A.生物利用度

B.血浆半衰期

C.稳态血浓度

D.治疗指数

E.潜伏期

用所给词的适当形式填空。（5分）

小题1:People are enjoying               (walk) around the town.

小题2: Gina decided                  ( forget) all her problems.

小题3:Who is the                 (funny) actor in the movie?

小题4: Don’t read this book ,because it is                (mean) .

小题5: The farmers expect                 (have) a harvest(丰收) this autumn.