How many students are there in each group— Usually each group _______ six students in our class.

I wondered if the man was our new headmaster but quickly______the thought， because he was too young．

Though I have no idea _______ the new film is about, I know it is popular with all who have seen it.

填入下面横线处的句子，最恰当的一句是（3分）某一地区特定时间内游客数量超过其接待能力，是造成该地区旅游业种种问题的重要原因。接待能力若不提高，再美的湖光山色也会黯淡无光， ，再好的微笑服务也会丧失魅力。

If he takes on this work, he will have no choice but ________ an even greater challenge.[ ]