①我国人民拥有的民主是真实的 ②我国人民的民主具有法律保障
③我国人民拥有的民主是广泛的 ④我国人民的民主具有物质保障
A：②④
B：②③
C：①③
D：①④
It’s 9:00 in the evening. The family are at home. Jim’s father sits in a chair. He’s watching TV(看电视). His mother stands near the window. She feeds(喂) the birds—Polly. Polly says, “Thanks! Thanks!” Where is Jim? Oh, he’s behind the door. Kate is looking for(找) him. They play games in Kate’s room.
下列用来分析生活、生产中化学知识的问题，正确的是
如果水银气压计没有竖直放置，所测数值与实际大气压相比将（ ）
用哺乳动物的红细胞制备用细胞膜的方法正确的是（ ）
