It is difficult to conceive how, even for those people well disposed to rule themselves, the attempt to achieve happiness should be rendered so （） by one single curse, that of a bad form of government.

The primary impulse of each human being is to（）himself,...

单项选择题The primary impulse of each human being is to（）himself, but the secondary impulse is to venture out of the self, to correct its provincialism and heal its loneliness.

Current estimates put thirteen percent of global flora ...

单项选择题Current estimates put thirteen percent of global flora at risk of extinction, but this number does not include （） plants from tropical regions, where the majority of the world's plants grow.

The teacher has （） catering to some students, but to re...

单项选择题The teacher has （） catering to some students, but to retain his tenure, which effects only after a teacher has unanimously gratified his students, he offers his complaints （）.