已知命题$p$：抛物线$y=2x^2$的准线方程为$y=-\frac{1}{2}$；命题$q$：平面内两条直线的斜率相等是两条直线平行的充分不必要条件；则下列命题是真命题的是（    ）

影响气候的主要因素：____、____、____。

Some damage has been caused u____ by people simply walking around the site and some has been caused deliberately.

已知某圆拱桥的水面跨度为20m，拱高为4m，现有一船，船宽为10m，水面以上高为3m，问这条船能否从桥下通过？