13.I need to choose a gift for my father.

我需要给我的爸爸买一份礼物。

还可说成：

A gift need be chosen for my father.

I need to pick up a gift for my father.

应用解析：

as you choose 随你喜欢，随你的便;can not choose but 不得不，只好;pick and choose 挑挑拣拣，挑剔;仔细挑选

14.We have serven-day statutary hollidays on National Day.

国庆节我们有7天法定假日。

还可说成：

On National Day, we have a week off according to the law.

Lawfully, we can be free for seven days on National Day.

应用解析：

statutory adj. 法定的，受法律约束的，依照法律规定的。例如：The statutory service is provided by local government social service committees.地方政府社会服务委员会提供法定援助。

15.We often play jokes with others on April Fool's Day.

在愚人节，我们经常和别人开玩笑。

还可说成：

On April Fool's Day, we oftern make fun of others.

We usually play tricks on others on April Fool's Day.

应用解析：

be no joke 不是闹着玩的事;see the joke 理解其中的可笑之处;joking apart 严肃地说，认真地说

16.I owe it all to my mother.

这都归功于我妈妈!

还可说成：

All is credited to my mother.

All this is due to my mother.

谚语：

Fear is interest paid on a debt you may not owe.

畏惧之害，在于无形。

17.Thanks for being such a great teacher. Happy Teacher's Day!

您真的是一名好老师，谢谢您，教师节快乐!

还可说成：

My sincere thanks to you for being my excellent teacher. Wish you a happy Teacher's Day.

I wish to express my thanks to you for being such a great teacher. Sincerely wish you a happy Teacher's Day!

应用解析：

a great part of 大部分，许多;be great at 善于，精通;in the great 总结

18.It is said that the moon is at its brightest and fullest tonight.

据说今晚的月亮是最亮最圆的。

还可说成：

The moon is said to become round and bright tonight.

I was told that the moon is full and bright tonight.

应用解析：

a half moon 半月;a new moon 新月;waning moon 亏月;a blue moon 不可能的事物，难得遇见的事物