The verb "tempered" is followed by the preposition "with," which means to moderate or soften something.

Experts have testified ____ the machine's excellent performance.
(a) at (b) on (c) for (d) away

The phrasal verb "taking on" means to undertake or assume responsibility for something. The provided answer key is (b). I will follow it. "Taking on" could mean arguing or taking a challenge.

The academic rigour of his lectures is fortunately tempered ____ wit.
(a) with (b) in (c) from (d) to

The idiom "take account of" is followed by the preposition "of." The provided answer key is (a). I will correct the answer key.

The phrasal verb "straying from" means to deviate from the main topic or path.

Have you taken account ____ all the possible shift in demand?
(a) on (b) into (c) with (d) to

The phrasal verb "stormed into" means to enter a place in a very angry way.

We are straying ____ the subject. The subject is what action is Humza likely to take.
(a) in (b) from (c) on (d) with

The phrasal verb "stir up" means to cause or incite trouble or strong feelings.

Navid stormed ____ the meeting waving a piece of paper.
(a) on (b) into (c) to (d) onto

The phrasal verb "stuck with" means to be burdened with or unable to get rid of a difficult task.

He is blamed for stirring ____ hatred between friends.
(a) up (b) in (c) on (d) of

The phrasal verb "stand for" means to represent or symbolize something.

We were stuck ____ the job of addressing a thousand envelops by the following morning.
(a) in (b) to (c) on (d) with

The phrasal verb "stand by" means to remain loyal to or support someone. In this context, it means to watch something happen without intervening.

What your second initial stand ____?
(a) for (b) in (c) with (d) by

The phrasal verb "standing about" means to stand or remain in a place without doing anything in particular.

A man may not stand ____ and watch another destroy himself.
(a) with (b) about (c) by (d) off