下列物质中能用来干燥NH3的是（ ） A．浓硫酸 B．碱石灰 C．AlCl3溶液

在对背信用证业务中，前一个信用证的受益人是后一个信用证的( )

A．开证行

B．通知行

C．开证人

D．受益人

治疗斑疹伤寒应首选

A．青霉素G
B．氨基糖苷类
C．大环内酯类
D．头孢菌素类
E．四环素类

Electronic mail and filing permit a user to compose and transmit a message on an office (71) system. In the early 1970s, the ARPANET community developed a number of such systems which have been heavily used. Through standard message format (72) , several hundred different computers and electronic mail interfaces are specification of how (73) and return addresses should appear on envelopes and which sizes are allowable for envelopes. In the electronic message world, they describe what (74) of characters are required at the (75) of a message to identify the sending and receiving mailboxes.

A．characteristic

B．style

C．sequences

D．format

表意性人物

羚角钩藤汤和天麻钩藤饮均具有的作用是（）

A.增液舒筋

B.清热活血

C.滋阴潜阳

D.平肝降逆

E.平息肝风