A:to choose
B:to have been chose
C:choosing
D:having been chose
一个长方形操场长120米,宽60米,画在练习本上,选取( )的比例尺比较合适.
下列化学仪器需垫加石棉网才能用酒精灯加热的是
A、试管 B、____ C、燃烧匙 D、蒸发皿.