harder是什么意思

　　He pulled harder on the rope, grunting with the effort.

　　他边用力边哼声，使出更大的力气拉绳子。

　　Successful venture capital investment is a lot harder than it sometimes looks.

　　成功的风险投资有时要比它表面看起来困难得多。

　　Work becomes harder with each passing day.

　　工作一天比一天辛苦。

　　The premise is that schools will work harder to improve if they must compete

　　前提是，如果各学校必须参与竞争的话，就会更加努力。