一次函数y=（2a+4）x-（3-a），当a为何值时：

（1）图象过原点？

（2）图象与y轴交点在x轴下方？

（3）图象不经过第二象限？

用be或have的适当形式填空

1. Tom's sister          tall and thin

2. Lucy and Lily both          long curly hair.

3. Mike          heavy and          two big ears.

4. The football player          of medium height.

5.I          of medium build and          short straight hair.