下列生殖方式属于有性生殖的是（ ）A．嫁接B．扦插C．组织培养D．播种
在容积固定的密闭容器中存在如下反应：A(g)+3B(g)2C(g)，ΔH＜0，某研究小组研究了其他条件不变时，改变某一条件对上述反应的影响，并根据实验数据作
如图，在矩形ABCD中，E、F分别是边BC、AB上的点，且EF＝ED，EF⊥ED．试说明AE平分∠BAD．
A little old couple walked slowly into McDonald ’ s on one cold winter evening. It seemed that they didn' t come to the right place with the young families and young couples eating that night. The l
At the beginning of class, the noise of desks ________ could be heard outside the classroom. A. opened and closed B. to be opened and closed C. being opened and closed
空气是人类赖以生存的自然资源。空气质量指标一般包括SO2、NO2、CO、可吸入颗粒、臭氧（O3）等，现新增颗粒物(粒径小于等于2.5μm)，即通常所称的PM2.5
默写。(10分)①单是周围的短短的泥墙根一带，就有无限趣味_____________、_______________________.②______________________，凭轩涕泗流。 (杜甫《登岳阳楼》)③居
