L17 Always young
本课单词和备注
appear v. 扮演；出现、浮现 disappear v. 消失
appear as 角色
she often appears on the stage as a young girl #appear..as..girl
she has appeared in over 30 movies #她参演了30多部电影
stage n. 舞台
on the stage 在舞台上
莎士比亚皆大欢喜：
All the world’s a stage,And all the men and women merely players;
They have their exits and their entrances,And one man in his time plays many parts,
bright adj. 鲜艳的
stocking n. 长筒袜
a pair of stockings 一双袜子
stock n. 现货
in stock 有货 outof stock 无货
sock n. 短袜
情态动词
情态动词都有一个基本意和推测意
情态助动词must
态：主动态、被动态（动词根据时态改变）
写句子的方法，语态+时态+情态（判断3个态）
语态：主语和动词的关系，主动还是被动
时态：动作的时间
情态：情绪和态度
must和have to的区别
在主观意愿上must（只能表示主观）；have to（可以表示主观或客观，更倾向于客观）
在客观意愿上，只能使用have to
We have to join the military service #我们必须去参加兵役（某些国家的兵役式强制的，属于客观事实，即使主观上不愿意）
must没有人称变化，have/has to有人称变化
现在:must主观；have/has to 主观/客观
we must do it again
将来:must + 将来时间；will have to
we'll have to do it again
过去：had to
we had to do it agin
1、大多情况下形式：主语+must+v.ed #无人称变化，接动词原形
2、过去时must改为had to，形式：主语+had to+v.ed
例句：
I had to go to the bank yesterday #must没有过去式也不能接，这里用have to过去式
It's late.I must go now #一般现在时，可以用must
I must get up early tomorrow #已经有未来时间状语引导可以用Must
She'll has to get up early #没用时间状语引导用will have/has to,三单用has
表推测：
He is in pain #100%，一般现在时
He must be in pain #90%，一般现在时
He was in pain #100%，一般过去式
He must have been in pain #90%，一般过去式,主系表结构
疑问句：（用must提问否定回答一般用needn't 或者 not have to）
——Must I go to medical school and be a doctor like you?
——No, you needn't, son. You are free to make your own decision. #needn't
用have to 进行提问，需要借助助动词do,Do you have to...
Have/Do you have to tell everyone our secrets?
must 和have to详解
课后练习
