如图，直线y=2x+2与y轴交于A点，与反比例函数 $y=\frac{k}{x}$ （x＞0）的图象交于点M，过M作MH⊥x轴于点H，且tan∠AHO=2．

在日本经济产生垄断组织的多种原因中，起主导作用的是（   ）

东东今年a岁，比妈妈小m岁，再过c年后，妈妈比东东大____岁。

阅读下文，回答问题
                                                                                                  On the beach
    It is a fine day. A lot of people go to the beach to enjoy sunshine. Some people are swimming like fishes in the sea. On the beach，some young people are playing volleyball.
    Some of them are lying under the coconut trees. And some old people are chatting with each other. What are the children doing? Look! They are making castles with spade and sand. They are having fun。
⑴⑵⑶⑷⑸根据短文内容，判断正误；⑹根据短文内容填空。

下列关于***的历史上的一些重要会议的叙述，有误的一项是（    ）