must / have to

1. must 意为“必须”， 通常表示命令或说话人主观认为必须要做某事，含强调语气，侧重主观性。

2. have to 意为“不得不”， 指受客观条件或环境迫使而“不得不”做某事，突出客性。

全部

1·We must get together sometime.

我们一定要找个时间聚一下。《牛津词典》

2·We must allow for human error.

我们必须考虑到人为的失误。《牛津词典》

3·This structure must be stable.

这种结构一定很稳固。《柯林斯英汉双解大词典》

4·Accurate records must be kept.

必须保存准确的记录。《牛津词典》

5·Your trip must have been fun!

你这次旅行一定很开心吧！《牛津词典》

6·These books must be very old.

这些书一定年头很久了。《柯林斯英汉双解大词典》

7·We must work together, brothers!

我们必须携手工作，伙计们！《牛津词典》

8·We must set realistic goals.

我们必须制订可实现的目标。《牛津词典》

9·You must get home before curfew.

你必须在实行宵禁以前回到家中。《牛津词典》

10·I must telephone my parents.

我一定要给父母打个电话。《柯林斯英汉双解大词典》

必须

1·We must support our weaker brethren.

我们必须支持弱势的同胞。《牛津词典》

2·You must act boldly and confidently.

你必须表现得大胆、自信。《柯林斯英汉双解大词典》

3·I must put my affairs in order.

我必须整理整理我的事务。《牛津词典》

4·We must set realistic goals.

我们必须制订可实现的目标。《牛津词典》

5·You must get it in writing.

你必须用书面的形式。《牛津词典》

一定

1·We must get together sometime.

我们一定要找个时间聚一下。《牛津词典》

2·His phone must be switched off.

他的电话一定是关机了。《牛津词典》

3·I must take you up on that point.

那个问题我一定要找你问个明白。《牛津词典》

4·The sign must be taken down.

这个指示牌一定要摘下来。《牛津词典》

5·She must be crazy to lend him money.

她把钱借给他，一定是疯了。《牛津词典》

得

1·I must go—I have a train to catch.

我得走了—我要赶火车。《牛津词典》

2·I'm sorry, but I must go now.

对不起，但是我得马上走。《柯林斯英汉双解大词典》

3·This came as a surprise, I must say.

我得说这发生得很突然。《柯林斯英汉双解大词典》

4·I must ask you not to do that again.

我得劝你别再那样做了。《牛津词典》

5·You simply must see the play.

那出戏你真得看看。《牛津词典》

应该

1·Children in single-parent families must not be stigmatized.

单亲家庭的孩子不应该受到侮辱。《柯林斯英汉双解大词典》

2·We must take a wider view.

我们应该从大处着眼。《新英汉大辞典》

3·You must not tell a lie.

你不应该撒谎。

4·We must see what can be done.

我们应该看看有什么能做的。《新英汉大辞典》

5·We must think of others.

我们应该多想想别人。

必须要

1·These shrubs must have an acid, lime-free soil.

这些灌木必须要有酸性、无石灰的土壤。《柯林斯英汉双解大词典》

2·I must look for a zebra crossing.

我必须要找斑马线。

3·You must listen to them carefully.

你必须要仔细听他们说。

4·I've got a long report I must dictate.

我拿到了一份我必须要口述的很长的报告。

5·You must warm up before you play football.

踢足球之前必须要热身。

须

1·All visitors must sign in on arrival.

来客均须签到。《牛津词典》

2·Children over the age of 12 must pay full fare.

12岁以上儿童须购全票。《牛津词典》

3·You must ask permission for all major expenditure.

一切重大开支均须报请批准。《牛津词典》

4·Children over five must pay (the) full price for the ticket.

五岁以上的儿童须买全票。《牛津词典》

5·It is laid down that all candidates must submit three copies of their dissertation.

根据规定所有的学位答辩人均须提交论文一式三份。《牛津词典》

务必

1·All visitors must report to the reception desk on arrival.

所有参观者到达后务必在接待处报到。《牛津词典》

2·Young people must awake to the risks of smoking and try to avoid this bad habit.

年轻人务必意识到吸烟的危害，尽量避免染上这样的坏习惯。

3·The international community must fundamentally revise its strategy.

国际社会务必从根本上修正其策略。

4·Lifetime relationships teach you a lifetime of lessons; those things you must build upon in order to have a solid emotional foundation.

一生的关系能赐予你一生的经验，但是你务必将这些东西建立在坚实的基础上以便于获得坚固的感情基础。

5·Its capital position must remain strong: capable of at least maintaining its lending book, absorbing shocks, and commanding enough confidence to allow borrowing without state guarantees.

那便是它的资本状况务必尚需雄厚：至少有能力维持放贷、缓解冲击及有足够的信心无需国家担保获得借款。

必

1·Being in love must have addled your brain.

坠入爱河必已使你神魂颠倒。《牛津词典》

2·This is a must have extension!

这可以说是一个必装的扩展！

3·To save what you love, you must sacrifice it.

要拯救那些你热爱的东西，必先让它作出牺牲！

4·But these reasons must all manifest themselves in brain architecture.

但这些原因必会在大脑结构中显现。

5·The return to the average investor is the market return minus costs; if costs rise, returns must fall.

普通投资者的回报等于市场回报率减去成本；如果成本上升，受益必会下降。

必须得

1·We must arrange this train into the train schedule.

我们必须得把这个列车安排进火车行车时刻表。

2·We must let them catch us up. . . .

我们必须得让他们赶上我们。。。

3·Nevertheless, I must ask you to sign this waiver, which relieves our corporation of responsibility for anything you or he may do or say for the duration of the effect.

不过呢，我必须得让你签署这份弃权声明。在药物起效期间，你和你的老公无论干了什么事、说了什么话，我们公司都不负任何责任。

4·But they must follow his rules, including putting up signs above their shop.

但是他们必须得遵守他的规矩，包括在店铺上方挂上招牌。

5·We must learn to appreciate each of our seasons if we want to bring fresh fruit.

假如我们想要时刻有所收获，我们就必须得学会欣赏我们生命的四季。

(1)must be一定；一定要；肯定是

(1)must have必须拥有；非有不可

(1)must have been一定（对过去事实肯定的推测）

(1)must have done必定做了…（表示对过去的推测）

(1)must be going该告辞了；必须去

(1)must be off[口]该走了