甲、乙两组同学中，甲组有3名男同学，3名女同学；乙组有4名男同学，2名女同学，从甲、乙两组中各选出2名同学，这4人中恰有1名女同学的选法有

A 70种 B 75种 C 80种 D 85种 E 100种

A 19岁 B 20岁 C 21岁 D 22岁 E 23岁

A 9 B 10 C 11 D <img src="https://www.beizhujiaoyu.com/uploads/202208/164066061371051.png" width="67" height="16" />  E <img src="https://www.beizhujiaoyu.com/uploads/202208/164066061728251.png" width="42" height="17" /> 

A 2组 B 3组 C 4组 D 5组 E 6组

A 2 B 3 C 4 D 5 E 6

A 0．8019 B 0．9989 C 0．999 D 0．9999 E 0．99999

A 4πm² B 6πm² C 8πm² D 12πm² E 24πm²

A <img src="https://www.beizhujiaoyu.com/uploads/202208/164066063795831.png" width="57" height="37" /> B <img src="https://www.beizhujiaoyu.com/uploads/202208/164066064125921.png" width="58" height="37" />  C <img src="https://www.beizhujiaoyu.com/uploads/202208/164066064665591.png" width="65" height="37" />  D <img src="https://www.beizhujiaoyu.com/uploads/202208/164066065176711.png" width="65" height="37" />  E <img src="https://www.beizhujiaoyu.com/uploads/202208/164066065869691.png" width="65" height="16" /> 

A 20 B 24 C 40 D 48 E 80

A 0．3 B 0．5 C 0．6 D 0．7 E 0．73