Sửa lỗi sai a) Harry didn't concentrate on his study, but he got bad mark in his test b) Tom hopes meeting new people at the party

sửa lỗi sai 
 a, harry didn't concentrate on his study ,but he got bad mark in his test
 b, tom hopes meeting new people at the party
 c, we learnt a lot of useful lessons since .we were students
 d, suzy fails to win a place in hanoi university last yeas