It is necessary for sb

必须───must;某人───someone

He must have picked up a cold — he's begun to snuffle.───他开始鼻塞,一定是感冒了.

We are in the same boat; we must help each other.───我们既然同舟, 就要共济.

The scenery for the play must have cost too much.───那出戏的舞台布景一定很费钱.

The wicked must be wiped out.───恶人必须除掉.

Owing to the limitation of our knowledge, there must be mistakes and errors in the book.───由于我们水平有限, 本书少不了会有缺点和错误.

The stew must be boiled up before serving.───炖肉必须煮熟才能上桌.

Hospital operating instruments must be sanitary.───医院的手术器械必须是消过毒的.

The realisation that the murderer must have been a close friend came as a shock.───意识到杀人凶手一定是个密友,大家都很震惊.

One must drink as one brews.

We must reinforce the troops at the front.

We must be consistent in applying the rules.

The fish is rotten; you must not eat it.

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