两条相对的经线组成一个经线圈，可以把地球分为两个半球．下列各组经线中，两条经线不相对的一组是（　　）

用方框中所给单词的适当形式填空，使对话通顺、正确。每词仅用一次（每空一词）。

Marie：Roy and Carla, what are your ideas for solving these pollution problems？

Roy：To cut down air pollution，we should take the bus or subway instead of   ____ 

Carla：Yeah, or ride a bike. There are other advantages of bike riding. It's good for health and it doesn't____   much！

Marie：Great ideas！What about waste pollution?

Carla：Mmm, I thank simple things like bringing a bag to go shopping can help. I started doing that a year ago.

Roy：Me，too. Also I never take wooden chopsticks or plastic____ when I buy takeaway food. I use the ones at home．

Carla：And remember to throw rubbish in the bins and keep____ places clean and beautiful for everyone·

Marie：So together, our actions can make a____ and lead to a better future！

如图是探究声音特性的小实验，回答下面问题：