1.every day是时间副词“每天”e.g.I go to school every day except Saturday and Sunday.；
everyday是形容词,“每天的”e.g.We have learned a lot of everyday English.
2.be popular with受……欢迎 更多人会用be popular with 例如：Loud music is more popular with young people than with old.be popular to意思和be popular with差不多,但是用法上有点区别 例如：If you want to impress your peers (friends) it is generally more popular to show them ,(to do this,to say,usage with the verb to be) your cool rDVD collection be popular for在...领域受欢迎 例如:Special English has become a very popular tool for teaching English