我来当回小法官（对的打“√”，错的打“×”）。  

1．如果最短的两条线段之和大于第三条线段，那么这三条线段就一定能围成三角形。[ ]

2．下面各组线段都能围成三角形。      

     ①2 cm    3 cm    4 cm        ②2 cm    3 cm    5 cm[ ]

3．三角形有无数条高。 [ ]

4．1厘米、2厘米、20厘米这三条线段不能围成三角形。[ ]

5．三角形任意两边之差小于第三边。[ ]

完成对话，根据下下文在横线上填上合适的句子。

A: Can I help you?

B: __1__ . I'm looking for a shirt for myself.

A: What size do you wear.

B: Size 40.

A: __2__ ?

B: Blue.

A: I think these will be very nice.

B: Can I try it on here?

A: __3__  .

B: (Coming out of the change room) I think it's OK. But I'm afraid it's a bit expensive. Can I get it at a

    discount?

A: Yes.  it's 10% off today.

B: OK. __4__ . By the way do I have to pay cash (现金)?

A: Yes. Only cash.(Handing over the shirt) Here you are.

B: Thank you.

A: __5__.