阅读短文，从A、B、C、D四个选项中选择最佳答案。

    Mr. White and his 1 wanted to do it by decided to paint the outside of their house. To save money they 2. On Saturday morning they bought some paint and two brushes. They began that afternoon 3 the back of the house. The next Saturday 4 went to a football match while his wife painted the 5 of the house. On Sunday they found they couldn't open 6 of the front windows. They got them all 7 in the end. But they 8 three of the seven which were very expensive to repair. Next time 9 10 try to save money, they'll certainly pay to do the work.

石油化工专家闵恩泽院士获2007年度国家最高科学技术奖，他是石油化工技术自主创新的先行者和绿色化学的开拓者，他研制的多种石油炼制催化剂极大地降低了我国石油化工产品的成本．

下面图形中，有两个直角的是____。