易爆物品仓库的大门应当向哪个方向开启？（）
A.内
B.外
C.上
D.下
参考答案：B
直线l1：2x+（m+1）y+4=0与直线l2：mx+3y-2=0平行，则m的值为______．
The human body is composed of organs, each ____ a definite job to do. [ ]
A. have
B. to have
C. has
D. having
