皮皮学，免费搜题
登录
搜题
【单选题】
可靠的端-端通信服务应该在哪层提供?( )A.
网络层
B.
运输层
C.
应用层
D.
数据链路层
拍照语音搜题，微信中搜索"皮皮学"使用
参考答案：
参考解析：
知识点：
皮皮学刷刷变学霸
举一反三
【单选题】He smiled as if he ____ my thought. A. read B. was reading C. had read D. has read
A.
B.
C.
D.
D
【简答题】（）又称自动开关，它是一种既有手动开关作用，又能自动进行（）、（）、（）、和（）的电器。它可用来分配电能，不频繁地启动异步电动机，对电源线路及电动机等实行保护，当它们发生严重的过载或者短路及欠压等故障时能自动切断电路，其功能相当于熔断器式开关与过欠热继电器等的组合。
【单选题】When he smiled it was as if you had just 29 him the funniest joke on earth. 29.
A.
made
B.
told
C.
played
D.
given
【单选题】The baby smiled as if he ______ what his mother said.
A.
was understanding
B.
understood
C.
h ad understood
D.
understands
【单选题】The boy smiled as if he ______ what his mother said.
A.
understands
B.
understood
C.
understanding
D.
have understood
相关题目：