将适量的橡皮泥捏在铅笔的一端，能使铅笔竖直浮在液体中，这就制成了一个很有用的土仪器密度计．将它分别放到盛有不同液体的杯中，静止时的情景如图所示．对于这个密度计所运用的知识或用途，下列说法中正确的是（　　）

如图是某农田长期使用一种农药的甲虫群体密度变化曲线，下列叙述中，不符合达尔文进化观点的是（　　）

阅读下面短文，按照句子结构的语法性和上下文连贯的要求，在空格处填入一个适当的词或使用括号中词语的正确形式填空。

    Today is Friday. Linda says to her aunt on the telephone. "Aunt Mary, I'm sorry. I can't go ____ your farm tomorrow. Let us meet next Sunday."

    Aunt Mary says, "Oh, I'm sorry to hear that. I have ____ new dog. It is two years old. You can play with it on my farm."

    Linda says, "What's ____ (it) name?"

    Aunt Mary says, "Wangwang."

    Linda says, "Is it brown?"

    Aunt Mary says, "No, it is black. You know, it's my favourite colour.

    Linda says, "Yes, I think Wangwang ____ I can be good friends. See you next Sunday."

    Aunt Mary says, "____ (see) you."