一般配合力（general combining ability）

特殊配合力（specific combining ability）

This is part of the process of ______ iron into steel.

A:corresponding B:conveying C:combining D:converting

The main road through Littlebury was blocked for three hours today after an accident ______ two lorries.

A:containing B:connection C:involving D:combining

John is collaborating with Mary in writing an article.

A:cooperating B:marrying C:combining D:arguing

John is {{U}}collaborating{{/U}} with mary in writing an article.

A:cooperating B:competing C:combining D:arguing

John is collaborating with Mary in writing an article.

A:cooperating B:competing C:combining D:arguing

We've been {{U}}doing{{/U}} with that company for many years.

A:comparing B:dealing C:keeping D:combining

In the following essay, each blank has four choices. Choose the best answer and write down on the answer sheet.
Spread spectrum simply means that data is sent in small pieces over a number of the （）frequencies availablefor use at any time in the specified range. Devices using （） spread spectrum (DSSS) communicate by （） each byte of data into several parts and sending them concurrently on different （） . DSSS uses a lot of the available （） , about 22 megahertz (MHz).

A:splitting B:combining C:packing D:compacting