The engine may lose power or slow down during running, when this occurs, the first cause possible may be hot bearings and （） of the pistons in the cylinders.

Turbocharging system may be designed to operate on either the （） or the constant pressure exhaust system.

我国民航Ku波段卫星通信网采用的多址技术是（）

In the closed cooling system, the water （）.

当前，通信业正在经历一场前所未有的变革，即从原来主要提供语音业务的电信通信业向提供包括语音、数据和多媒体业务的信息通信业转变，这种变革就是（）。

在现代通信电源系统中，通信用（），已成为各种通信设备必不可少的供电组成部分。

There is a （） system lubricating the running gear and cooling the piston and sometimes lubricating the cylinders.

为了保障海上移动通信的畅通，国际电信联盟将海上通信划分为四个优先级别，分别是（）。

通信系统中，称调制前的电信号为（）信号，调制后的电信号为（）信号。

As to the piston cooling, of the following, which statement is not true?（）

The piston cooling system may employ similar components, except that （） is used instead of a head tank.

The cooling of the piston is carried out by circulating （） across the underside of the crown and inside the ring belt or through specially shaped passages.