4．C　根据后一句话可知，美国人有时用狗来形容那些行为不善良、吝啬的人。故选C。

　　5．A　根据前一句话可知，此处指在美国语言中，人们用狗来描述天气的一些表达方式，而"rain cats and dogs"表示"倾盆大雨"，符合语境。故选A。

二.语法填空

　　Joe: Hi, Barbara. Have you lost __1__ (weigh)?

　　Barbara: Hi, Joe. Yeah. I've been on __2__ diet for a couple of months now.

　　Joe: Wow. You look great.

　　Barbara: Thanks for noticing.

　　Joe: What type of diet were you on?

　　Barbara: I joined a health club and my trainer __3__ (give) me tips on eating. I managed __4__ (lose) 15 pounds in two months.

　　Joe: That's __5__ (amaze). What tips did your trainer give you?

　　Barbara: Mostly on how to exercise, but the best advice__6__ I got was changing my __7__ (eat) habits. Instead of eating three times a day, she told me to eat five times a day.

　　Joe: That doesn't make sense.__8__ you eat more, then how do you lose weight?

Barbara：__9__(actual), I was eating the same amount. I ate five __10__ (small) meals a day and I usually do.