Questões Militares de Inglês - Infinitivo e gerúndio | Infinitive and gerund

In the alternatives below, the gerund was used correctly in only two sentences.

(1) This laptop is definitely worth buying.

(2) He stopped eating fast food in order to lose weight.

(3) They can't afford buying a new car.

(4) She refused seeing him.

The correct sentences are:

Which of the alternatives completes the sentence correctly?

"As a teacher, the thing that annoys me most is (1) ___. 

Which of the alternatives below completes the sentence correctly? 

(1) _____ is a bad habit and it can cause lung cancer. 

Which sequence best completes the text below?

We ’re in danger of (1)___ locked in the midfield stalemate of agreement, so allow me (2)____ up the left wing. Given the extraordínary wealth of top flight football in this country, I do think the game owes a greater degree of pastoral care to its players, and of a more profound nature than (3)____ out their cars and living arrangements. Football clubs now gain control over players when they1re youngsters, but not nearly enough effort is put into (4)___ rounded, educated individuais.

(Adapted from http://www.guardian.co.uk)

Choose the alternative that fills in the blank in the sentence below.

Scientists say that when a person stops _____ very soon, the chances of getting cancer and other diseases reduce.