The mass of

an electron is so small as _______.

I am proud

to … English for 30 years.

She seems ____ by an insurance company.

The company

will have … a new trading centre next year.

The Earth behaves as if it … a

large magnet.

If you enter our University,

you ____

If I … you, I would look

through those figures once more.

If a “short-circuit’ _______ at any

place in a circuit, a very large current is caused to flow.

If he had written his paper

a

week ago, it ____ by now.

If specialists had found a

suitable technique, they ____ difficulties with their experiments.