畅想的英文：
think BIG
give free rein to one's imagination
pamper imagination
give the reins to one's thoughts

参考例句：

Shepherds plays reed with beautiful imagine, returns with a haunting melody, here comes spring.
牧童吹奏着牧笛归来，他用美丽的畅想萦绕着飘荡的音符，这是春天的脚步声。

think是什么意思：
v. 认为；想；琢磨；试想；预期；一心想；计划；记得

I think and think and cannot cease from thinking.
我想了又想，一直想个没完。

Think of solar power, and you probably think of photovoltaic panels.
当考虑到太阳能，你一定会想到光伏电池板。

Do you think it will rain? -- Yes, I think so.
你看会下雨吗？是的，我想会下雨。

big是什么意思：
adj. 大的；庞大的；量大的；重要的
adv. 夸大地；大量地

Big, Big, Big....Innuendo, deleted
老大哥，老大哥，老大哥……

big commerce, big circulation, big market
大商业，大流通，大市场

You are big in america.
你在美国是个大人物。

give是什么意思：
n. 弹性，伸展性
v. 给；授予；赠送；捐赠；供给；告诉，提供；产生；让步；塌下；举办；支付

Will you give it a shot?
你想做尝试吗？

He gives twice who gives quickly

The purpose is not to give an exhaustive treatment.
其目的并不是给出全面彻底的处理。