Word formation - nouns
Infinitive vs gerund
Word formation - prefixes
Informal vs formal
Articles
100

react

reaction

100

I regret (miss) my appointment.

missing

100

likely and legal

unlikely and illegal

100

go on

continue

100

I´d love to learn to play a/the/- piano.

play the piano
200

major, weak

majority, weakness

200

Would you mind (open) the window?

opening

200

reliable and responsible

unreliable and irresponsible

200

find out

discover

200

Not enough is being done to help a/the/- homeless.

help the homeless

300

appear, resign, govern

appearance, resignation, government

300

Our teacher always makes us (do) long homework!

do

300

tolerant, pleasant and competent

intolerant, unpleasant and incompetent

300

carry out

conduct, (do)

300

My brother is a/the/- librarian, but he goes to gym at least five times a/the/- week.

a librarian, five times a week

400

original, explain, sad, tolerate

originality, explanation, sadness, tolerance

400

Try (rest) for a while, you might feel better then. It´s no use (cry). 

to rest, crying

400

experienced, mature, satisfied and reliable

inexperienced, immature, dissatisfied and unreliable

400

put off

discourage / postpone

400

We are going to a/the/- mountains rather than a/the /- coast.

the mountains, the coast

500

able, lonely, convert, assist, obey

ability, loneliness, conversion, assistance, obedience

500

Liz suggested (fly) to New York, but I couldn´t afford (pay) the flight.

flying, to pay

500

sociable, competent, obedient, practical, decisive

unsociable, incompetent, disobedient, impractical, indecisive

500

get worse

deteriorate

500

Many famous comedians attended a/the/- Oxford University. It is in a/the/- England, in a/the/- United kingdom.

attended Oxford university, in England, in the UK