种植98棵银杏树，成活98棵，成活率是98%．______．（判断对错）
9898×100%=100%；
故答案为：错误．
Many teenagers enjoy the book Harry Potter _____ by J·K·Rowling. [ ]
A. written
B. was written
C. was writing
简述低温预热开关QA56及交流加热空气断路器QA72的作用。
