凸透镜对光有 ____作用（选填“会聚”或“发散”）．凸透镜的焦点为F，当蜡烛如图所示放置时，在透镜另一侧可成一个 ____、放大的实像（选填“倒立”或“正立”）

阅读下面短文，从A、B、C、D四个选项中选出最佳选项。

    David is a good student at school, but he is not clean. His face and hands are often dirty. He washes them with water only. He doesn't like to use soap(肥皂). He has an aunt. His aunt comes to see him. She looks at David and says, " David, I know what you ate for breakfast this morning." "What?" David looks at his aunt and asks.

"Eggs," says his aunt. "Your face and mouth tell me that."

    "You are wrong, my dear aunt!" says David. "Not today or yesterday, but the day before yesterday."