A.超声波碎石
B.风力发电
C.机械钟计时
D.打桩机打桩
答案:D
Who is the inventor of paper? [ ]
A. Chinese people
B. English people
配制100mi酸乳,需在鲜牛乳中加入10%乳酸多少毫升( )。
A.0.3B.0.4C.0.5D.0.6E.0.7