21. Sam is __________ to pass all the final examinations because he is working very hard.

A. probable        B. likely        C. maybe        D. possible

22. Always remember to put such dangerous things as knives out of children’s _______.

A. touch            B. sight                C. reach            D. distance

23. Honesty is a basic element in friends-making and that is ______ it requires to keep ever-lasting friendship.

A. how          B. what         C. whether      D. which  

24. On 14 April, 2018, US President Donald Trump asked that the US     Syria.

A. come down with     B. gave way to       C. declare war against   D. rise up against

25. The question of ____ English will keep on changing in the future is easy _____.

A. if; to be answered        B. whether; to answer

C. whether; to be answered   D. that; to answer