根据短文理解，从A、B、C、D四个选项中选择最佳答案填空。

    Allan was worried. This was his first time to go traveling by 1. He didn't know how to find his 2, so he went to the air hostess (空姐) and asked, “Could you 3 me? I can't find my seat. ” The air hostess showed him the seat and told him to 4down and fasten the seat belt (系好安全带). She told Allan not to move about when the plane was going up. And she also said that Allan's ears might feel a little 5, but he didn't need to 6 about it because many people felt like that. When the plane was flying very 7. Allan could stand up and walk around. He could either read 8, newspapers or see films. The air hostess would 9 food and drinks. Allan would enjoy the flight and 10 soon.

人的眼睛像一架神奇的照相机，晶状体相当于凸透镜，视网膜相当于胶片，通过晶状体的调节将远近不同的物体成像在视网膜上。如图所示是不同位置处的两个物体的成像示意图，由图得出：眼睛看近处的物体时，晶状体的焦距____(选填“变大”、“变小”或“不变”)。人眼若长期观察近处物体，会造成晶状体过度弯曲，当他看远处物体时，像会成在视网膜的前方，应戴____透镜制成的眼镜加以矫正。