You must play a spade if you have one.

你如果有黑桃牌，就必须打出来。

《牛津词典》

You must play a diamond if you have one.

如果你有方块就必须出。

《牛津词典》

To play against them you must play with your head and not just your heart.

同他们比赛你不仅需要用心去比赛而且需要用头脑。

youdao

At the end of the day, once your company crosses the line into the public markets, you must play by the same old rules.

FORBES: Tech Execs Successors To The Robber Barons, Says Newsweek

In lending to family, you must play around two big sand traps -- the rules governing no-interest loans and the IRS' desire to recast family loans as gifts.

FORBES: Sue your sister!

Today you must play perfectly.

NPR: Lang Lang: A Life In Music, So Far