Through which of the following processes does alternating current (AC) get converted to direct current (DC)?

Play it by the ear

Select the option that best conveys the meaning of the bold idiom in the sentence.

Which word or words explain the meaning of the following idioms;

Step up the plate

Up against the wall

Select the most appropriate meaning of the given idiom.

Cat and dog life

In the following question, out of the four alternatives, select the alternative which best expresses the meaning of the idiom/phrase. 

Hang in there

To pick holes

Do a roaring trade