The important thing is that this is a major breakthrough. “breakthrough” here means an important development or achievement.

Generally speaking, suction heads require to be （） for high speed or large capacities than for low speed or small capacities.

It should be apparent that little or nothing is gained by opening a drain at the same time as or after admitting steamThe above sentence probably means （）.

 ______ twice a year, whether it is a car or a bus or a truck, is the rule that every driver must obey in this city.

The guard, fencing or shielding for moving parts or machinery can be removed for repair only when the machinery it belongs to（）

Is this（）longer or shorter?

（）uses one or two high pressure pumps for all the cylinders with one more standby, while（）have a separate high-pressure pump for each cylinder.

（）, or drum is used for hauling in or letting out the wires or ropes which will fasten the ship to the shore.

The （） is used for hauling in or letting out the wires or ropes.

Banks have no liability for any delay or loss caused by postal or telex failure.

By saying “While it’s true that ..., be they scientific or artistic” (Lines 1-3, Para.5), the author means that _____.

Any alteration of course and／or speed to avoid collision shall，if the circumstances of the case admit，（）to another vessel observing visually or by radar.