填料式补偿器沿管道中心线安装，不得（）。
参考答案：偏斜
There was a _____ look on his face. He found what the expert said too difficult to understand.
A．puzzle
B．puzzling
C．puzzled
D．to puzzle
在(1-x3)(1+x)10的展开中，x5的系数是（ ）。
