水萃取倒空前必须将顶部苯顶完。
参考答案:对
下列关于声的论述中,正确的是( )
A.声只能传递信息
B.声只能传递能量
C.声有时传递能量,有时传递信息
D.声传递信息和能量是同时进行的
Only when _________ the tea-house _______ it was the same place he’d been in last year. [ ]
A. did he reach; he realized
B. he reached; he realized
C. he reached; did he realize
D. did he reach; did he realize