13. 心墙坝或斜墙坝施工，坝面应向上倾斜(  )的坡度。

、<span>1%</span><span>－</span><span>2%</span>

、<span>3%</span><span>－</span><span>4%</span>

、<span>4%</span><span>－</span><span>5%</span>