阅读下面材料，选择恰当的句子填入文中空白处，使短文内容完整、意思连贯。

Some people say life is like crossing a river. 【小题1】

I think our life is much like climbing a mountain. Each year we have a new mountain to climb. To reach our goals, we work hard to make progress day after day. 【小题2】 We can complain（抱怨）about how unfair it is to climb a new mountain every day. Or, we can just make ourselves busy.

Sometimes, we fall over. Here we also have another choice. 【小题3】 Or, we can stand on our feet and begin climbing that mountain again.

If we reach the goal for this year, we start from zero to reach the goal for next year. We shouldn’t spend the rest of our lives looking at where we used to be. 【小题4】

Many people will waste time worrying, “Can I reach my final goal?” or “Is it worth doing”? 【小题5】 The question is, “Can I take the next step in the right direction?”

Take one step at a time, and pay attention to tomorrow’s step today.

A．Here we have a choice.

B．That is not the question.

C．Instead, we should look ahead.

D．We can stop and complain about what progress we have lost.

E．Some say it is like climbing a mountain.