Standing on the platform, Professor Li kept silent for a moment,         on the audience below.

The great hall was crowded with many people, ______ many children ______ on their parents’ laps.

____ abroad for two years, the two astronauts went back home last year.

Tom concluded his lecture ________ that he couldn’t emphasize enough how important our efforts were.

Jack, who claimed ______ everything clearly, however, he told a lie.