Question 21.

• aeroplane

• the aeroplane

• an aeroplane

Question 22.

• quite a

• a quite

• quite

Question 23.

• are trying

• try

• had tried

Question 24.

• little

• few

• a little

Question 25.

• to fly

• in flying

• into flying

Question 26.

• this

• next

• last

Question 27.

• were

• is

• was

Question 28.

• who

• which

• what

Question 29.

• who

• which

• what

Question 30.

• His

• Their

• Theirs