不能降低杂交的背景染色的是
E
暂无解析
Apersonisluckyifhiscareer________withhisinterestandhobby
Peopletodayarehighlyconcernedaboutthequalityoftheairthey___(breath).
我国必须在社会主义条件下经历一个相当长的初级阶段，以便实现（）
Weallknowaboutthe_____thatsmokingcandotoourhealth.
Nowthatyouknowallthefacts，youcanmakeaninformed___(choose).