New words：

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详细词源拆解：

词汇家族

必记高频搭配

关键使用提醒

New words：

sufficient /səˈfɪʃnt/ adj. 足够的；充足的

详细词源拆解：

词根 suf-（在下，充分）+ fic（做）+ 形容词后缀 -ent
本义 “做得足够到位的”，指数量、程度能够满足需求，书面正式用词。

必记高频搭配

sufficient for sth 足够应付某物

The water here is sufficient for our daily use.

sufficient to do sth 足以做某事

This money is sufficient to buy a new schoolbag.

sufficiently (adv. 充分地)

He is sufficiently prepared for the coming exam.

sufficiency (n. 充足)

We have a sufficiency of books for reading.

关键使用提醒

1. 固定搭配两种结构：

   ① sufficient + 名词 + for sth
   ② sufficient + 名词 + to do sth

2. 语气区分：sufficient > enough，作文书面替换 enough 提升档次

   反义词：insufficient adj. 不足的，不够的
   Insufficient rest will make you tired easily.
   休息不足会让你很容易疲惫。

3. 副词 sufficiently 修饰形容词、动词，置于被修饰词前

   She is sufficiently brave to speak in public.
   她足够勇敢，敢于当众发言。

New words：

suffice /səˈfaɪs/ vi.足够；足以

详细词源拆解：

前缀 suf-（充分、到位）+ 词根 fic（做）；书面正式用词，本义事物数量、程度达标，能够满足需求。

词汇家族

suffice (v. 足够)
→ sufficient (adj. 充足的)
→ sufficiently (adv. 充分地)
→ sufficiency (n. 足量，充足)
→ insufficient (adj. 不足的)

必记高频搭配

suffice for sth 足够应付某物

This bag suffices for all my school things.

suffice to do sth 足以做某事

Half an hour suffices to finish this exercise.

suffice it to say that… 长话短说；只需说……（书面高级句型）

I won’t go into all the details. Suffice it to say that the whole event was a complete disaster.

关键使用提醒

1. 同义句型替换（写作提分）

   sth suffice to do = sth be sufficient to do = have enough sth to do
   One hour suffices to read this story. = One hour is sufficient to read this story.
   一小时足够读完这个故事。

2. 高级固定句式 suffice it to say that…，议论文、书信均可使用

   Suffice it to say that practice makes perfect.
   只需说，熟能生巧。

3. 语法使用规则：不及物动词，后接介词 for，不能直接加人作宾语

   错误：The bread suffices us
   正确：The bread suffices for us

4. 语体区分：suffice、sufficient 偏向正式书面；enough 口语、普通作文通用。

New words：

depress/dɪˈpres/
v. 动词

使抑郁；使消沉；使情绪低落
抑制；压低；使（价格、经济）不景气

详细词源拆解：

前缀 de-（向下）+ press（按压）
字面义 “向下按压”；
引申两层含义：情绪被压低 → 使沮丧；数值、物价被压低 → 抑制、降低。

词汇家族

depress (v. 使沮丧；压低)
→ depressed (adj. 感到沮丧的；萧条的)
→ depressing (adj. 令人压抑的)
→ depression (n. 抑郁；萧条；洼地)

必记高频搭配

depress one’s mood 使某人心情低落

The bad news depresses everyone in the class.

depress prices 压低物价

Too much supply will depress the price of fruit.

depressed (adj. 令人感到低落的)

I am depressed after watching the depressing movie.

depressing (adj. 事物令人压抑的)

The depressing story depresses all readers.

depression (n. 低落情绪，萧条)

He fell into deep depression after losing the game.

关键使用提醒

1. 区分两类形容词（考试高频考点）

   depressed → 修饰人，表示 “感到沮丧的”
   depressing → 修饰事物，表示 “令人压抑的”

2. 及物动词用法：直接接人 / 物作宾语，无需加介词

   Sad songs depress her.
   悲伤的歌曲让她心情低落。

3. 经济类词义阅读常考：depress the economy 使经济萧条
4. 名词 depression 多义：情绪抑郁、经济大萧条、地面洼地。

New words：

hesitate /ˈhezɪteɪt/ v.（对某事）犹豫；顾虑；疑虑；踌躇；迟疑；不愿

详细词源拆解：

词根 hesit（黏住、停滞）+ 动词后缀 -ate
本义脚步停滞不前；
引申为内心迟疑、犹豫，不敢立刻行动或开口。

词汇家族

hesitate (v. 犹豫)
→ hesitation (n. 犹豫，迟疑)
→ hesitant (adj. 迟疑的，犹豫的)
→ hesitantly (adv. 犹豫地，迟疑地)

必记高频搭配

hesitate to do sth 犹豫做某事

Many kids hesitate to speak in front of the whole class.

don’t hesitate to do sth 尽管放心做某事（书信高频）

If you need help, don’t hesitate to call me.

hesitate about /over sth 对某事犹豫不决

She hesitated over the choice of two after-school classes.

hesitation (n. 迟疑) [ˌhezɪˈteɪʃ(ə)n]

He agreed without any hesitation.

hesitant (adj. 犹豫的) [ˈhezɪtənt]

He is hesitant and always hesitates before making choices.

关键使用提醒

1. 书信万能句型：Don’t hesitate to contact me. 如需联系，不必客气。

2. 名词搭配：without hesitation 毫不犹豫（写作加分短语）

   He helped me without hesitation.
   他毫不犹豫地向我伸出援手。

3. 否定含义高频用法：

   否定祈使句 don’t hesitate to do 表鼓励、客气邀约。