阅读下面材料，从A、B、C、D四个选项中选出一个最佳选项。

    Car-hailing company DiDi signed an agreement with TAL Education Group to provide free online courses for the children of taxi drivers. The courses, worth 30 million yuan, cover all subjects from primary to high school. Children can study courses at home, saving parents' time to spend or pick up children from off-line after-school classes.

    According to Zhu Jingshi, vice president of DiDi, all 153 million registered (注册) taxi drivers of DiDi can ask for the courses on the company's mobile app. The car-hailing company will evaluate (评价) the drivers and provide courses on the basis of the time they became registered drivers with the company, the number of passengers served and evaluation from passengers.

    The health and education of children have remained top priorities of Chinese parents, including taxi drivers. A survey done by DiDi and TAL showed that although the average monthly income (平均月收入) of taxi drivers is only 6000 yuan, many would like to pay 40 percent of their income for their children's education.

    The survey found that most taxi drivers were born in the 1970s and 1980s and worked seven days a week. More than 70 percent of them have children under 18 but very few have time to be with family and children. Only 8 percent of them said they had guided their children in doing homework. Because of these, 60 percent of drivers hope their children could receive the guidance from professional services.

小明帮父母收获玉米时，发现有些“玉米棒子”上只有很少的几粒玉米．你认为造成这些玉米缺粒最可能的原因是        (    )

《清文献通考》卷33载，“（顺治四年）户部议复两广总督佟养甲疏言：‘佛朗西国人寓居濠镜澳，以其携来番货与粤商互市，盖已有年。后深入省会，至于激变，遂行禁止。今督臣以通商裕国为请，然前事可鉴，应请仍照前明崇祯十三年禁其入省之例，止令商载货下澳贸易可也。’上从之。”这段记载充分说明

关于实验基本操作方法的归纳错误的是(    )