阅读短文，根据文章的内容填词，每空一词。
Lucy and Ann are good friends. They are from different countries. They are now in China. They are both in Class 3. Lucy is twelve, but Ann is eleven. Lucy is from the USA. She arrived in China 3 years ago. And Ann is from English. She is in China for two months. They both speak English. Lucy usually goes to school on foot. Ann usually goes to school by subway. Mr. Yang is their Chinese teacher. Lucy is good at Chinese. But Ann can only speak a little Chinese. Mr. Yang and Lucy often helps her study Chinese.
小题1:Lucy and Ann are in the _____ class, but they come from _________ countries.
小题2:Lucy ________ in China _________ three years.
小题3:Lucy usually _________ to school and Ann _______ the subway to school.
小题4:Lucy _______ _______ in Chinese.
小题5:Lucy often helps Ann ________ _________ Chinese.
，在x=1处可导，则（）。