28．-I’m sorry to have brought you so much trouble．
- .
A．My pleasure B．That's all right
C．No problem D．You’re welcome
27．-The film Avatar made by James Cameron is fantastic．Don’t you think so?
- ．For years to come it will be beyond what movies can achieve．
A．Hopefully B．Extremely C．Exactly D．Surprisingly
26．In a tight job market, what you wear to an interview could be the difference between getting
An and getting rejected.
A．answer B．offer C．honor D．effort
25．-Sorry，Mum, I lost my key to the bicycle again．
-Oh! How you be so careless! You have to learn to look after your belongings．
A．can B．may C．must D．dare
24．In the last six to nine months，teens in the US to text messaging in numbers twice
that in Europe and Asia．
A．took B．have taken C．had taken D．would take
23．As time went on, new customs went into Christmas，and was the Christmas tree，
which was started in Germany．
A．it B．this C．that D．one
22．Some researchers believe that many patterns of nature are rules of their own and not
affected by natural selection．
A．making B．breaking C．following D．bending
第一节：单项填空(共15小题；每小题1分，满分15分)
从A、B、C、D四个选项中，选出可填入空白处的最佳选项。
21．-Can I look at the menu for a few seconds before I decide?
-Of course． ，sir．
A．Take your time B．It doesn’t matter
C．Enjoy yourself D．Help yourself
31．(16分) 某学生兴趣小组为了探究光照、二氧化碳不足分别对光合作用的影响，将叶片
用打孔器打出小圆片数片，抽取小叶圆片内气体使之下沉于冷开水中置于黑暗处备用，实验
中根据在不同条件下小叶圆片上浮所需时间的长短推测光合作用的相对强弱。请回答：
(1) 实验1：取一小烧杯，编号A，加入一定量的冷开水；再加入一定量的粉末，
使其在水中溶解；用纱布包裹小烧杯后，置于适宜温度下水浴保温；放入小叶圆片10片，待小叶圆片下沉于水底，将小烧杯置于日光灯下；记录叶片上浮所需时间。
①参照实验1请简要写出实验2应变化的条件：
。
②参照实验1请简要写出对照组应变化的条件：
(2) 实验结果：
实验组1： 。
实验组2： 。
对照组： 。
(3) 上述实验的自变量是 ；上述实验还可以根据
推测因变量的变化。
(4) 浸没于水中的小叶圆片上浮的原因是 。
粉末，