安装法兰连接时，螺栓应对称拧紧。
参考答案：对
At last,nothing but some trees remained,with some branches________the wall.[ ]
A．stick out of
B．to stick out
C．sticking out of
D．to stick out of
其性趋下的病邪为
A．火邪
B．燥邪
C．湿邪
D．风邪
