I need to buy an umbrella.
我需要买一把伞。
A I like this suitcase very much. It's very light.
A 我非常喜欢这个手提箱。它非常轻便。
B Good. What's next? What else do you want to buy?
B 好。下面买什么？你还要买什么？
A I need to buy an umbrella.
A 我需要买一把伞。
B Yes. You need one at this time of year. It's very wet.
B 好的。一年的这个时候需要伞。天气很潮湿。
A I think I need a heavier coat, too.
A 我想我还需要一件厚一些的衣服。
B I know just the place! There’s a shopping mall just along the street.
B 我知道哪里卖！在这条街上有一个购物中心。

Notes注释
1 To talk about what you need, need / need, and why, for example an umbrella, an umbrella / an umbrella and, a coat / a coat when the weather is wet / wet – you can say: I need to buy an umbrella. / I need to buy an umbrella. : You need one at this time of year. / You need one at this time of year. : I think I need a heavier coat, too. / I think I need a heavier coat, too.
要谈论你需要什么，need /需要，以及为什么需要，如当天气潮湿时需要一把伞，an umbrella /一把伞，和一件衣服，a coat /一件衣服，你可以说：I need to buy an umbrella. /我需要买一把伞。You need one at this time of year. /一年的这个时候需要伞。I think I need a heavier coat, too. /我想我还需要一件厚一些的衣服。
2 If you have a good idea about where to buy something, you can say: I know just the place. / I know just the place.
如果你对去哪里买某样东西有好主意，你可以说：I know just the place. /我知道哪里卖！

Key phrases and sentences
I like this suitcase very much.
It's very light.
Good. What's next?
What else do you want to buy?
I need to buy an umbrella.
Yes. You need one at this time of year. It's very wet.
I think I need a heavier overcoat, too.
I know just the place!
There’s a shopping mall just along the street.

我非常喜欢这个手提箱。它非常轻便。
好。下面买什么？你还要买什么？
我需要买一把伞。
好的。一年的这个时候需要伞。天气很潮湿。
我想我还需要一件厚一些的衣服。
我知道哪里卖！
在这条街上有一个购物中心。