You have to know the number of spiders.

你需要确定蜘蛛的数量。

youdao

Johnson won't answer the phone if he doesn't know the number.

如果约翰逊不知道号码，就不会接电话。

youdao

Do you know the number of the people coming to the party?

你知道来参加晚会的人数吗？

youdao

Citrus growers know that the number of fruit in their current crop has an inverse effect on the number of flowers in the return bloom.

VOA: special.2009.11.10

I bet there are people in this room who know the lyrics to over 1,000 songs, NBA know the number of every individual in the National Basketball Association, so I think that learning some subset of elements is not unreasonable.

我敢打赌这个房间里有那么些人,他们能记得住超过1000首歌的歌词，记得住,每个人的号码，因此我认为,能记住这些元素也不是不可能的。

麻省理工公开课 - 固态化学导论课程节选

Now, the critical thing to understand about a corporation is that in order to value a share in a corporation you absolutely have to know the number of shares outstanding.

理解这类公司的关键在于,要衡量一家公司股票的价值,你必须清楚总共发行的股票数量

耶鲁公开课 - 金融市场课程节选

You want to know the number one killer of all small to medium size businesses?

FORBES: 7 Deadly Roadblocks for Startup Entrepreneurs

In the workforce, well, it's probably - I don't know the number exactly.

NPR: The Hidden Costs and Benefits of Illegal Immigration

The first time someone hears the word trillion, they might not know the number of zeros but they know it's a big number.

BBC: Is trillion the new billion?