Every year in Australia there are crocodile (鳄鱼) attacks (攻击) on humans. Two years ago, a 24-year-old German tourist died when she went {#blank#}1{#/blank#} in a lake. Although there were signs warning people that there might be crocodiles, the girl and {#blank#}2{#/blank#} friends decided to have a midnight swim. The girl {#blank#}3{#/blank#} disappeared and the next morning her body was found. Near it was a four-meter crocodile. And only last month two{#blank#}4{#/blank#} boys watched in fear as their friend was killed by a crocodile. They were washing their mountain bikes in a river at that time. Then, those two boys climbed a tree and stayed there for 22 {#blank#}5{#/blank#}while the crocodile waited below.

A: You must be really {#blank#}1{#/blank#} about leaving for America tomorrow, Li Ping!

B: Yeah. But I'm a bit nervous.

A: Nervous about what?

B: I don't know many of the {#blank#}2{#/blank#} and manners in the US. Could you give me a hand?

A: Sure.

B: What {#blank#}3{#/blank#} do they have in America?

A: Well, it's important to be on time when you're invited for dinner. It's {#blank#}4{#/blank#} to arrive late. Americans expect their guests to be on time.

B: Then how long may I stay there?

A: After the meal, don't leave at once. Or you seem to have come only for the meal. When your friends seem to be getting tired and running out of things, it's time to leave. The next day, call or write a thank-you note to say how much you {#blank#}5{#/blank#} the evening.