New Words：

whether [ˈweðər] conj.（表示迟疑或两个可能性之间的选择）是否

Sample Sentences：

I'm going whether you like it or not .
I'm not sure whether I should tell you this.
He seemed undecided whether to go or stay.
I'll see whether she's at home(= or not at home) .

New Words：

prepare [prɪˈper] v. 准备;把…预备好;使(自己)有准备;

Sample Sentences：

I had no time to prepare.
How much food should we prepare?
He was in the kitchen preparing lunch.
I'm not prepared to discuss this on the phone.

New Words：

free [friː] adj. 自由的；免费的；随心所欲的；不受限制的

Sample Sentences：

I don't have much free time.
It's a free country; I'll say what I like!
The breakfast is free; you need't pay for it.
How much of their free time do you think children in your country spend on reading?

New Words：

sour [ˈsaʊər] adj. 酸的;有酸味的

Sample Sentences：

This pear tastes a bit sour.
The fruit is still green and eats sour.
I like fruit. But I don't like grapes. They're sour.

New Words：

ripe [raɪp] adj.成熟的；时机成熟的

Sample Sentences：

Was the peach ripe or green?
Don't pick those apples until they are ripe.
They decided to wait until the time was ripe.