题干

选修4-4:坐标系与参数方程
将圆 {x=2cosθ,y=2sinθ θ 为参数)上的每一个点的横坐标保持不变,纵坐标变为原来的
1
2
,得到曲线 C
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同类题3

阅读下列文段,回答文后问题。
        码头上的人,全是硬碰硬。手艺人靠的是手,手上就必得有绝活。有绝活的,吃荤,亮堂,站在大街中央;没能耐的,吃素,发蔫,靠边呆着。这一套可不是谁家定的,它地地道道是码头上的一种活法。自来唱大戏的,都讲究闯天津码头。天津人迷戏也懂戏,眼刁耳尖,褒贬分明。戏唱得好,下边叫好捧场,像见到皇上,不少名角便打天津唱红唱紫、大红大紫;可要是稀松平常,要哪没哪,戏唱砸了,下边一准起哄喝倒彩,弄不好茶碗扔上去,茶叶沫子沾满戏袍和胡须上。天下看戏,哪儿也没天津倒好叫得厉害。您别说不好,这一来也就练出不少能人来。各行各业,全有几个本领齐天的活神仙。刻砖刘、泥人张、风筝魏、机器王、刷子李等等。天津人好把这种人的姓,和他们拿手擅长的行当连在一起称呼。叫长了,名字反没人知道。只有这一个绰号,在码头上响当当和当当响。
        刷子李是河北大街一家营造厂的师傅。专干粉刷一行,别的不干。他要是给您刷好一间屋子,屋里任嘛甭放,单坐着,就赛升天一般美。最叫人叫绝的是,他刷浆时必穿一身黑,干完活,身上绝没有一个白点。别不信!他还给自己立下一个规矩,只要身上有白点,白刷不要钱。倘若没这本事,他不早饿成干儿了?

同类题4

根据短文内容, 从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

    While serious training is important for all dogs, playtime is just as important.____ Use these games to help teach your dog how to play.

1)Hide and Seek

    Hide and seek isn't just for kids. Dogs can really enjoy this game. Pick up one of your dog's favorite toys or treats. Tell your dog to stay.____ When you are ready, call your dog to come to you. If possible, squeak(使吱吱叫)the toy or shake the treats. Reward your dog with praise and the toy/treat when she finds you.

2)Fetch

    Many dogs have a natural ability to fetch. Other dogs can be taught how.____Play indoors with a soft toy or outdoors in a fenced-in area with a ball or disc. For dogs that really  love to run, try this game of fetch!

3)Find the Treat

    Dogs have superior senses of smell, and most love to use their noses to find food. Let your dog use her brain and her nose to find hidden goodies. First, have your dog stay out of sight. Then, hide her favorite treats in various places around the room.____ If help is needed, you can lead her around or point to areas for her to explore.

    Whatever the game, safety comes first! Remember to watch your dog for signs of exhaustion or overheating when you are playing. Stop if your dog seems tired or shows signs of anxiety. ____When other dogs or people are around, it may create a dangerous distraction(分神).

A. Then, go to find a good hiding place.

B. Try different games to see which your dog responds to best.

C. A good game of fetch can be played almost anywhere.

D. You can include games in training as well.

E. Also be aware of your surroundings when playing with your dog.

F. Encourage your dog to play with other dogs.

G. Bring your dog back in and tell her to “go find!”