当a=3，b=4时，代数式3a-4b+6=______．
将a=3，b=4代入，则3a-4b+6=-1．
如图，将平行四边形ABCD向上平移1个单位长度，可以得到四边形A′B′C′D′，画出平移后的图形，并指出其各个顶点的坐标．
The room needs for three people.
[ ]
A. to be big enough
B. to big enough
C. to be enough big
D. enough big to be
