Is Tom at school today?No, He ’s at home ______ he has a bad cold.

The first step in the study of any language is observing and ____ precisely what happens when native speakers speak it.

Great as Newton was, many of his ideas ____ today and are being modified by the work of scientists of our time.

____ what may, we’re not going to make any concessions to his unreasonable demands.

只有在我过度劳累的时候，在我长时间不间断地工作的时候，在我感到内心空虚，需要充实的时候，我才会感到寂寞。有时，外出演讲回来，见了许多人，讲了许多话，心中满是纷乱的体验需要整理，偶尔也会觉得孤独。于是有那么一会儿，我会感到整个房子非常大，空荡荡的。不知此时的自我又藏匿于何处。这时，我会给花草浇浇水，挨个瞅瞅，仿佛它们是活生生的人一样，或是喂喂两只小猫，亲手做顿饭菜，这样自我就慢慢地重新找回。