例如983－296，精确计算983－296=687，用整十或整百数估算980－300=680

965－196，精确计算965－196=____，用整十或整百数估算____－____=____

下列关于人类起源和发展的说法不正确的是（   ）

如图所示，下端封闭且粗细均匀的“7”型细玻璃管，竖直部分长l=50cm，水平部分足够长，左边与大气相通，当温度t₁=27℃时，竖直管内有一段长为h=10cm的水银柱，封闭着一段长为l₁=30cm的空气柱，外界大气压始终保持P₀=76cmHg，设0℃为273K，试求：

①被封闭气柱长度为l₂=40cm时的温度t₂；

②温宿升高至t₃=177℃时，被封闭空气柱的长度l₃．

    Kent Wilson gets up at 5: 00 every morning. He is a dog walker. People 1 him to take their dogs for a walk.

    First Kent picks up five dogs from their homes. He takes them to the park in 2 car. The dogs run around and Kent plays games with them. He sometimes takes them to the beach. The dogs love that place, because they like to play in the 3. After an hour, Kent puts the dogs back in his car. He takes each dog home. Then Kent picks up another five dogs. Kent takes 4 dogs for a walk every day—ten in the morning and five in the afternoon. When it is 5 or snowy, Kent still takes dogs for a walk, but he will dry (把……弄干) them with a towel before he takes them home. He 6 each dog when they arrive home. He stays with the dog and watches it eat. He won't 7 until the dog finishes eating.

    "This job is very 8 work and doesn't pay very well, but I love it," says Kent. Kent also helps people take care of their pets when they are away. "I 9 to take care of all kinds of pets—cats, birds, mice and fish," says Kent, "but I don't have any pets at home. I'm so busy that I have no 10 to take care of them!"