民事法律行为所附的以下条件中符合法律要求的是( )。A．如果你在去年的收入达到了2

I found        __not easy to learn English well.       [ ]

A. that              

B. this              

C. it

下面七情直接伤及内脏的叙述中，哪条是错误的( )

A．惊伤肾

B．悲伤肺

C．怒伤肝

D．喜伤心

E．思伤脾

生命伦理学研究的主要内容是（）。

A.义务论

B.公益论

C.公平理论

D.生命道德理论

E.生命科学

利用数字签名可以实现以下3项功能：保证信息传输过程中的完整性、发送者身份认证和【 】。

Many students do not like tostudy history(历史)．They say that there are (41) many names and dates to (42) ．But if we do not know about the (43) ，we can not understand the present well．For example，if we wish to know how men (44) to use fire，we have to know what men did (45) the past to travel at night or to keep themselves (46) in cold nights．Only a study of history will make US realize(意识到) (47) everything we do today is the result of what (48) people did in the past．

[A] others [B] other [C] another

As we (49) history，we learn many interesting (50) ．History helps US understand our present life better．