在生物的分类等级中，包括生物种类最多的是（　　）

甲酸、乙酸、碳酸、苯酚的酸性由强到弱的顺序是（　　）

They wouldn’t agree to sell the house to us at the same price ______ they had promised, ______ was rather disappointing.

根据我国1951年以来824个气象站点最低气温资料，统计得出全国各农业区的无霜期，结果见表，我国各地无霜期空问分布的总体规律是（     ）

A: Hey, Ben! I need your help.
B: ____ ?
A: Linda's birthday is coming.____ ?
B:____ a photo album?
A: No, that's too boring.
B: Why ____  get her a scarf?
A: I think it's too personal.
B: Well, maybe you can hang out this weekend and then decide ____ . to buy?
A: Thank you!
B: You are welcome..