David is from America. He and his family____(have) different plans for the coming holiday. David likes China very much and he____ (go) to Beijing last year. But he wants to know more about Chinese culture so he____ (visit) Beijing again. This time he is going to the Palace Museum. There____ (be) many interesting things about Chinese culture there. He____ (want) to take lots of photos of the things in the Palace Museum. He____ (show) them to his friends. David's father ____ (read) many books about Japanese history three months ago. He thought some things in Japan were interesting. He____ (take) a trip to Japan. David's mother didn't know where to go at first. At last she ____ (decide) to go to Singapore. She likes the climate (气候) there. What about David's sister? She ____ (stay) at home and do her homework.

嫦娥工程分为“无人月球探测”、“载人登月”和“建立月球基地”三个阶段．如图所示，关闭发动机的航天飞机，在月球引力作用下，沿椭圆轨道由A点向月球靠近，并将在椭圆轨道的近月点B与空间站对接．已知空间站绕月圆轨道的半径为r，周期为T，引力常量为G，月球半径为R．下列说法中正确的是（   ）