11. fortunately ['fɔitʃənitli]adv.幸运地
Unfortunately, the accident happened but, fortunately, 98% of the passengers escaped. 事故不幸地发生了，但98%的旅客幸运地逃脱了。
Fortunately he met a good person when he was lost in that strange place. 很幸运，他在一个陌生的地方遇到了一个好人。
12. nutritious [nju:'triʃəs]adj.有营养的
Education is nutritious to the richness of your thought. 教育是一个人的精神食粮。
Milk is thought to be nutritious. 人们认为牛奶有营养。
13. decide [di'said ɔn]vi.&vi. 选择；做决定
Have you decided to stay or to leave? 你决定了是留还是走？
It is hard to decide between these two. 两者之间很难抉择。
decide on
Don't decide on important matters too quickly. 不要匆忙作重大决定。
To decide on the right person is even harder than to decide on a good career. 选择正确的人比选择正确的职业还难。
14. substitute for ['sʌbstitju:t]vt.&n.
vt. 用...代替，代以，代替
The company substituted John for Jones and the business took on a better look. 公司用琼斯替代了约翰，生意出现了新局面。
If you cannot go, would you please find someone to substitute for you? 如果你去不了，你可以找个人替代你吗？
n. 替代品；替代物
Water is not a proper substitute for wine. 水是不能代替酒的。
Would you like to substitute for me tomorrow? 明天你愿意替我当班吗？
15. unavailable ['ʌnə'veiləbl]adj.得不到的, 没空的
I’m afraid Dr. Hart is unavailable now. 哈特先生现在没空。
In this desert, vegetables are unavailable and water is scarce. 在这片沙漠，没有蔬菜，水也缺乏。
Can all these handouts available tomorrow before noon? 这些课堂讲义明天中午之前能准备好吗？
16. serve [sə:v]vt.
1) vt. 招待；为…服务
On Christmas Eve the old lady served the kids with candies. 在圣诞夜，这位老妇人给孩子招待糖果。
The servant has served his landlord for thirty years. 这位佣人服持她的主人长达30年。
2) vt. 食用；提供；端上
This company serves a meal at noon to all staff. 公司给员工提供午饭。
This restaurant serves good food.
3) vi. 服役；度过(服役)时间
She served three years in prison for abusing her son. 她因虐待儿子被判刑入狱三年。
He served in the military base for 10 years. 他在军队上服役了10年。
17. instead [in'sted]adv.代替
If you cannot write your own name, please leave your fingerprint here instead. 如果你不会写自己的名字，在这里划个押。
He did not cry over his failure; instead, he laughed and started anew. 他没有为失败哭泣；相反，他大笑并开始了新的冲刺。
18. offer ['ɔ:fə]vt.&vi.&n.提供
1) vt. 提供，出价
How much can you offer for this antique? 这件古董你出价多少钱？
If I may, I'd like to offer you a bit of advice. 如果可以的话，我想给你一两个忠告。
2) vi. 出现，显现；允许
She travels whenever the opportunity offers. 只要有机会，她就会去旅行。
He offered to give me coupon instead. 相反，他提出给我优惠券。
3) n. 出价, 提议
I am open to any offer. 我接受任何报价。
Your boss is making a good offer. You should not hesitate. 你老板正给你提供一个好机会，不要错过。
19. affect [ə'fekt]vt.
1) vt. 影响, 作用
His health was greatly affected by the bad weather. 坏天气严重影响了他的健康。
Tax increases have affected us all. 提税影响到每个人。
2) vt. 感动
The audience was deeply affected. 听众被深深地打动了。
He was affected by the sad news. 坏消息让他难过。
20. appetizing ['æpitaiziŋ]adj.令人开胃的
The roast beef is really appetizing. 烤牛肉让人胃口大开。
The color and the texture of the food make it more appetizing. 这份食物的颜色和造型都让人胃口大开。