阅读下面短文，在空白处填入1个适当的单词或括号内单词的正确形式。

Of all the events in the universe, solar eclipses may lead to the 【小题1】(great) change in animal behavior.【小题2】(puzzle) animals that are active during the day head back to their night places while night animals think they've overslept.

When the sun, moon and the earth are 【小题3】 a straight line, there will be an eclipse, so that the moon completely 【小题4】(block) the sun. Around the world, when a solar eclipse occurs, unusual phenomena in animals are often reported.

Some spiders start breaking 【小题5】(they) nets during the eclipse, just as they usually do at the end of the day. Once the solar eclipse has passed, they will start to rebuild them. 【小题6】(similar) , fish and birds, 【小题7】 are active during the day, go to their night resting places while bats come out. They seem to be tricked by 【小题8】 sudden darkness.

Once it 【小题9】(observe) that hippos in Zimbabwe left their rivers during an eclipse, and headed towards their night 【小题10】(feed) places on dry land. In the middle of their journey, the solar eclipse passed, daylight returned, and the hippos gave up their efforts.