正确答案: B

Ⅰ＋Ⅱ＋Ⅲ＋Ⅴ

题目：消除螺旋桨鸣音的具体办法是将桨叶随边0.4R～0.8R部分（）等抗鸣边缘，从而改变涡流引起的振动频率，也就不会与桨叶固有振动频率产生共振。Ⅰ.加厚；Ⅱ.减薄；Ⅲ.形成锯齿状；Ⅳ.质量改变；Ⅴ.钻孔。

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学习资料的答案和解析：

[单选题]The term （） refers to one complete sequence of operations required to produce power in an engine.

cycle

[单选题]With the shell and cap assembled as for running, a check must be made that the clearance between the cap and the housing （）.

are suitable