题干

科学家在研究细胞膜运输物质时发现有下列四种关系,分别用下图中四条曲线表示,在研究具体的物质X 时,发现细胞膜运输物质X的方式是协助扩散,下列哪些曲线可表示这种运输方式(  )

A:②④

B:②③

C:①③

D:③

上一题 下一题 0.0难度 选择题 更新时间:2019-03-25 12:19:36

答案(点此获取答案解析)

B

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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!”