1. D.
Dựa vào câu : Every year students in many countries learn English. Some of these students are young children. Others are teenagers. Many are adults. Some learn at school, others study by themselves. A few learn English just by hearing the language, in film, on television, in the office, or among their friends.
2.A.
Dựa vào câu: Most people must work hard to learn another language.
3.B.
Dựa vào câu :Many boys and girls learn English at school because it is one of their subjects.
4.B.
Dựa vào câu:They study their own language, and mathematics.... and English (In England, or America, or Australia, many boys and girls study their own language, which is English and mathematics....
5.D.
Dựa vào câu :Many adults learn English because it is useful for their work.