如图所示，活动发射平台载着质量为m的“神舟十号”和质量为M的火箭，在车的牵引下缓慢地驶向发射场．若行驶过程可视为匀速直线运动，则“神舟十号”、火箭受到的合力分别为（   ）

    For hours after their boat sank, Ken Henderson and Coen trod(踏) water in the Gulf of Mexico, talking about life and death while struggling to survive. For more than 30 hours, it worked.

    Then Henderson was forced to make a decision. “I'm going to go for help or you're not going to make it,” Henderson told Coen, just before cutting the strap(带子) that connected them in the deep, cold waters. “I understand,”Coen responded, giving Henderson a last set of instructions, “Kiss my babies for me.”

    Days after the fishing trip ended in tragedy, Henderson told the story for The Associated Press.

    They had been fishing for a few hours when suddenly Coen noticed the boat was filling with water. Henderson got both motors roaring, only to have the saltwater that had leaked in break them straight away…Coen jumped to the right, his sunglasses and cap flying off. The two grabbed extra life jackets and other floating items, including a half full bottle of Diet Coke.

    “The water was so cold and it took your breath away,” Henderson said. They immediately began to tremble.

    The pair prepared for a long wait. And they talked.

“We discussed things and discussed life. We discussed families. We just tried to keep occupied,” Henderson said.

    Eventually Coen started hallucinating(有幻觉). Henderson tried to keep Coen's arms and legs moving. But as morning came, Coen's situation worsened. And so Henderson decided to cut the strap.

    He swam for two hours, tired, frustrated and depressed. Then he saw an oil rig(钻探平台) in the distance. He swam, seeing ice and crystal trees in the water. He reminded himself constantly there were no trees.

    His legs was so weak that he could barely lift them. Henderson slowly pulled himself up the rig's ladder.

    It was over 50 miles from where they had gone in the water.

    All he could think of was Coen. Convinced his friend would survive, he told the coast guard where they had parted.

    Two hours later, a fisherman found a body in a life jacket.

    Later, in the hospital, Henderson saw his friend. He apologized and asked for forgiveness. He promised to realize his wishes and look after his girls.

    “I felt like a part of me had died out there,” Henderson said.

驿路梨花（节选）

    我们正在劳动，突然梨树丛中闪出了一群哈尼小姑娘。走在前边的约莫十四五岁，红润的脸上有两道弯弯的修长的眉毛和一对晶莹的大眼睛。我想：“她一定是梨花。”

    瑶族老人立即走到她们面前，深深弯下腰去，行了个大礼，吓得小姑娘们像小雀似的蹦开了，接着就哈哈大笑起来：“老爷爷，你给我们行这样大的礼，不怕折损我们吗”?

    老人严肃地说：“我感谢你们盖了这间小草房。”

    为头的那个小姑娘赶紧摇手：“不要谢我们!不要谢我们!房子是解放军叔叔盖的。”

    接着，小姑娘向我们讲述了房子的来历。十多年前，有一队解放军路过这里，在树林里过夜，半夜淋了大雨。他们想，这里要有一间给过路人避风雨的小屋就好了，第二天早上就砍树割草盖起了房子。她姐姐恰好过这边山上来拾菌子，好奇地问解放军叔叔;“你们要在还里长住?”解放军说：“不，我们是为了方便过路人。是雷锋同志教我们这样做的。“她姐姐很受感动。从那以后，常常趁砍树、拾菌子、找草药的机会来照料这小茅屋。

    原来她还不是梨花。我问：“梨花呢?”

    “前几年出嫁到山那边了。”

    不用说，姐姐出嫁后，是小姑娘接过任务，常来照管这小茅屋。

    我望着这群充满朝气的哈尼小姑娘和那洁白的梨花，不由得想起了一句诗：“驿路梨花处开”。