U2____TÌm lỗi sai________________________ 1. LAST YEAR(A), my son WAS LOST(B) AMONG(C) the crowd when we HAVE GONE(D) shopping. 2. ALMOST(A) 300 million people HAD VISITED(B) AMERICA’S NATIONAL PARKS(C) EVERY YEAR(D). 3. They HAVE STUDIED(A) english BEFORE(B) they WENT(C) TO LONDON(D). 4. They HAVE GOT MARRIED(A) For(B) 30 years BY(C) the end of THIS MONTH(D). 5. They WILL HELP(A) you WHENEVER(B) you WILL ASK(C) THEM(D)