若点A(m-3,1-3m)在第三象限,则m的取值范围是( ).
A:m>13
B:m<3
C:m>3
D:13<m<3
①带有不同基因的雌雄配子间的组合
②等位基因间的组合
③两亲本间的组合
④非同源染色体上非等位基因间的组合.
连线。
①Can your father play football? ____ A. Yes, she can.
②Can she ride a bike? ____ B. Here you are.
③Here's a card for you. Happy Teachers' Day! ____ C. No, he can't.
④Give me a balloon, please. ____ D. Thank you.
(I)证明:点H为BE的中点;
(II)若AB=AC=2 2 ,AB⊥AC,求直线BE与平面ABP所成角的正切值.
如图,△ABC与△DEF是位似图形,位似比为2:3,则△ABC与△DEF的面积比为 ____