![](https://static.youtibao.com/asksite/comm/h5/images/m_q_title.png)
In the first paragraph, the author introduces his topic by______.A.explaining a phenomenon
In the first paragraph, the author introduces his topic by______.
A.explaining a phenomenon
B.justifying an assumption
C.posing a contrast
D.making a comparison
![](https://static.youtibao.com/asksite/comm/h5/images/solist_ts.png)