目前在钻井工作中经常使用的钻头分为（）类。A、2 B、3 C、4 D、5

根据短文提示,请将下列的图片所代表的地点按Uncle Michael的行程顺序排列.

Uncle Michael likes going sightseeing for vacation .His office is in New York,

but he usually travels from one place to another. Last Monday he was in Tokyo.

Three days later he was in Australia. The day before yesterday he was in

Beijing . Last night he was in Shanghai. But now he is on the way to Tibet. He is

going there for a week. How busy he is !

A       B            C  

D         E            F

正确顺序:B→(66     )→ (67     )→ ( 68     )→( 69     )→ ( 70    )

下列哪一种动物是传播乙脑病毒的主要动物宿主（）

A.鼠

B.兔

C.鸟

D.蝙蝠

E.猪

我国神话保存的情况如何？

叙述女式翻翘式发型的吹梳技巧。

只见于RNA而不见于DNA的碱基是

A．A
B．T
C．G
D．C
E．U