如图所示，重力80N的物体在大小为20N，方向水平向右的拉力F₁作用下，在水平面上以2m/s的速度做匀速直线运动。当撤去拉力F₁，物体静止后，改用方向水平向左，大小为30N的拉力F₂使物体向左运动10m，在力F₂作用过程中(    )

中国入世过渡期于2016年12月结束，中国的完全市场经济地位从此应该得到承认。然而美欧一些发达国家在此问题上表现出了很多不确定性。欧盟表示，将于今年下半年决定是否承认中国完全市场经济地位；美国政府更意图设置障碍，警告欧盟一旦承认中国完全市场经济地位，无异于“单方面解除”欧洲对中国的贸易防御。这进一步佐证了（    ）

    Some boys like wearing the same kinds of clothes as girls, and some of them have long hair. So sometimes it's hard to tell whether(是否) they are boys or girls.

    Today is Sunday. I have a walk with my grandmother in the park. My grandmother is 80 years old and she can't see well. After some time, my grandmother is tired(疲倦的), so she sits down on a chair. There is another person sitting on the chair, too.

    “Hello,” my grandmother says to the person with long hair next to her. “Can you see the girl with long hair under the big tree?”“The girl?” says the person, “No, he's my brother Mike.”

    “Oh, sorry. I don't know you are his sister.” Says my grandmother.

    “No, I'm not his sister, I'm his brother!”