曲线y=e^﹣x+1在点（0，2）处的切线与直线y=0和x=0围成的三角形面积为（　　）

:We're going camping in the forest this weekend. What shall we do then?

:Let's go hiking and collect leaves.

:Sounds great! I want to ____stars(星星)at night，too. That's beautiful.

:I'd like to take some ____. There're many flowers in the forest.

:Good idea! But first，we should ____the tent on the grass. And l want to catch fish in the river. Because your mum ____eating fish.

:Thanks，dear! And we can build campfire and cook fish ____our tent.

下列人类美好的理想不属于化学家研究的范畴的是（ ）