姬粉盗体长2.5mm~3mm,椭圆形,赤褐色;复眼小,两复眼在腹面距离约为复眼直径的();颊终止于复眼前方,不向后延伸遮盖复眼。
A、3倍
B、4倍
C、5倍
D、6倍
参考答案:C
As is known to all, theory is based on practice and _____ serves practice.
A.in hand
B.in turn
C.in return
D.in exchange
压力容器构成中有下列这些元件()
A.壳体
B.支座及连接件
C.密封元件
D.开孔
E.水泥基础