избрать правильное слово1) We are trying to decide (if/whether) to go to

Избрать правильное слово
1) We are trying to decide (if/whether) to go to the sea in summer or not.
2) Secondary education in Russia is (compulsory/optional).
3) (No one/None) of my schoolmates has applied to a university abroad.
4) In this college students have to pay for their (learning/tuition).
5) The supply of food you have may (continue/last) for about a month.
6) Who can give me advice (if/whether) to do another foreign language?
7) Sally (mustnt/ neednt) worry about going to the shops: it is my turn to do the shopping.
8) I wondered if there were any pupils in the classroom and found out that there were
(nobody/none).
9) (Advanced/Advance) technologies are finding their way to schools.
10) I have three mobiles, but (no one/none) is expensive.