01.She said she had some difficulties in English pronunciation
02.There are some differences between the spelling of British English and American English
03.This is the reason of he being late for school
04.Mary.could you please help me to do my homework?
05.A large number of birds come to Kungming to overwinter everyyear
06.do sports activities
07.in modern times
08.Join the school team
09.Every 3 days；Every 4 days
10.Join the match
11.Contend medals
12.Hold the Olympics