In Canada and the United States, people enjoy entertaining(请客) at home. They often invite friends over{#blank#}1{#/blank#}a meal, a party, or just for coffee and conversation.

    Here are the {#blank#}2{#/blank#} (kind) of things people say when they invite someone to their home:

    "Would you like to come over for dinner Saturday night?" "Hey, we {#blank#}3{#/blank#}(have) a party on Friday. Can you come?" {#blank#}4{#/blank#}(reply) to an invitation, either say thank you and accept, or say you're sorry and give an excuse: "Thanks, I'd love to. What time would you like me to come?" {#blank#}5{#/blank#} "Oh, sorry. I've tickets for a movie."

    Sometimes, {#blank#}6{#/blank#}, people use expressions that sound like invitations but which are not real invitations. For example: "Please come over for a drink sometime." "Why not get together for {#blank#}7{#/blank#} party sometime?" "Why don't you come over and see us sometime soon?"

    They are really just polite ways of {#blank#}8{#/blank#} (end) a conversation. They are not real invitations because they don't mention a specific(确定的) time or date. They just show that the person is trying to be {#blank#}9{#/blank#} (friend). To reply to expressions like these, people just say "Sure, that would be great!" or "OK. Yes, thanks."

    So next time when you hear {#blank#}10{#/blank#} sounds like an invitation, listen carefully. Is it a real invitation or is the person just being friendly?

    Modern-day robots are programmed to handle tasks that are normally carried out by humans. They are faster and{#blank#}1{#/blank#}(accurate) than human workers and never ask for a pay rise or take breaks!

    Robots are also able to work{#blank#}2{#/blank#}dangerous situations.

    Researchers at the University of Arkansas in the United States say that the mobile robots which have been created already are ideal for the job of hospital attendants. These mobile robots store a{#blank#}3{#/blank#}(detail) map of the hospital in their memory. The robots' sensors can detect{#blank#}4{#/blank#}(object) and quickly get out of the way. Although these robots cannot go up and down know how{#blank#}5{#/blank#}(press) a button of an elevator.

    Researchers at a Massachusetts' university are creating the first robot {#blank#}6{#/blank#}can constantly change its shape according to the task it has to do. These are called polymorphic robots. "Polymorphic" means{#blank#}7{#/blank#}ability to take different forms. A 3D printer{#blank#}8{#/blank#}(place) inside the robot to create the desired shape. The entire process of changing forms in this manner is called the rapid printing technology which is{#blank#}9{#/blank#}(fair) common in the car industry to produce complex 3D structures quickly. Once the robot has performed{#blank#}10{#/blank#}(it) task, it can be melted down and recycled into another useful part by the 3D printer.