下列仪器既能做反应器，又能直接在酒精灯上加热的是（ ）
A．试管
B．烧杯
C．量筒
D．集气瓶
答案：A
矩形一边为6cm，两条对角线交角为60°，则对角线长为______．
This _____ my sister and those _____ my parents. [ ]
A. is; is
B. are; are
C. are; is
D. is; are
