Concentrate
On sth
Compete
Against/with sb
Compete for/in sth
Difficult
To do
Find sth difficult
Find it difficult to do
Fond
Of sth
Free
To do
Free from/of sth
Free for sth
Interested
In
Involve
Sth
Involved in sth
Listen
To sth
Love
Sth
Love to do
Mean
To do
It means that
It means sth
Prefer
To do (rather than do)
Prefer sth rather than sth
Prefer sth
Stop
Sth
Stop to do
Stop sb from doing sth
Sure/certain
Make/be sure/certain that
Sure/certain to do
Be sure/certain of sth