分析文段中画线句子的特点及表达效果。

关于下列说法，不正确的是（    ）

影响亚洲河流流向的主要原因（    ）

根据短文理解，选择正确答案。

    There are fifty students in our class. There are twenty-four boys and twenty-six girls. Some students live near the school, and some others live far from school. About half of the students usually come to school by bike. They often get to school at a quarter to seven. About fifteen students often come to school by bus. They often get to school very early, too. Another ten students come to school on foot. Their homes are near the school, but they are often late for school, because they get up late.