小儿夏季长期发热，秋凉自愈的临床意义是（） A.血虚 B.气虚 C.阴虚

I didn’t pass ________ math exam held last week. I always feel I am ________ failure at school.

A．An; /

B．the ; /

C．/ ; a

D．the ; a

Even though Jack has failed many times in his experiment，he holds a belief________he will succeed one

day if he carries on with it.[ ]

A．what  

B．which

C．whether  

D．that

一个质量为0.25kg的玻璃瓶，盛满水时称的质量是1.5kg，若盛满某种液体时称的质量时1.5kg．那么此液体的密度是______．

黄连、黄柏粉末显微特征有何异同？