在探究“物体的浮沉条件”的实验中，小明将一个新鲜茄子浸没在水中松手后，茄子上浮直至漂浮在水面上．为了使漂浮的茄子沉下去，小明将一根铁钉全部插入茄子中．从物体受力的角度来看，小明在茄子中插入铁钉是为了改变______力的大小，从而使浮力______（选填“大于”、“等于”或“小于”）重力．
在新鲜茄子中插入铁钉，新鲜茄子的重力增大；当重力大于浮力时，物体就会下沉；
故答案为：重；小于．
| 阅读理解。 |
| Mary is an American girl. She has two brothers, but she has no sisters. Both (两者都) her brothers like playing the guitar. Mary's father likes playing the trumpet. He is a teacher of a trumpet club. Her mother likes playing the piano. She can play it very well. Mary is twelve years old. She will go to China with her parents next week, because her parents find new jobs in China. |
| 1. How many people are there in Mary's family? |
[ ] |
| A. Five. B. Four. C. Six. D. Seven. |
| 2. What does Mary's father like playing? |
[ ] |
| A. The piano. B. The trumpet. C. The drum. D. The violin. |
| 3. Mary's parents and brothers like ______. |
[ ] |
| A. shopping B. music C. China D. trumpet |
| 4. What does Mary's mother like doing? |
[ ] |
| A. She likes playing the guitar. B. She likes playing the violin. C. She likes playing the piano. D. She likes shopping. |
| 5. Who is going to China? |
[ ] |
| A. Mary. B. Mary's brothers. C. Mary's parents. D. Mary and her parents. |