科学家观察并描述自然现象。

Scientists ___observe and describe natural phenomena.

研究人员在森林里待了数月，观察气候变化的影响。

Researchers spent months in the forest, ___observing the effects of climate change.

幼儿通过观察周围的人学到很多东西。

Young children learn a lot by ___observing the people around them.