秦岭-淮河是我国一条重要的界线，下列界线与她大体一致的是 （ ） ①暖温带与中温带分界线 ②冬季0℃等温线 ③800mm等降水量线 ④半湿润与半干旱分界线
A：①②
B：①④
C：②③
D：③④
Our teachers have been with us for nearly three years _______ we came to junior high school. We should thank them for what they have done for us.
