A. to observe B. observing

C. observed D. observes

解析:observe在这里表示庆祝，用不定式表示目的。

答案:A

归纳与迁移

(1)vt.看到，注意到，观察：observe what/how/where...；遵守（规则、法令等）；庆祝；评述，说（自己注意到的情况）

Tom is observing the movement of a cloud. 

汤姆在观察一片云的移动。

The girl sat and observed how her mom cooked. 

小女孩坐着看妈妈怎么做饭。

observe the laws/rules

遵守法律/规则

Mary will observe her birthday by making a trip to Shanghai.

玛丽将去上海旅行以庆祝她的生日。

"He is kind. " I observed. 

我说："他很善良。"

(2)see，watch，notice，observe，hear，feel，have， make等动词用不带to的不定式作宾语补足语，但在被动结构中必须带to。不定式指动作的全过程；现在分词指正在进行的动作的一部分，且表主动意义。

The police observed the man entering the bank.

警察看见那个人正走进银行。

The police observed the man enter the bank.

警察看见那个人走进银行。（整个过程）

The man was observed to enter the bank by the police. （同上）

要点2　curious

【例题】 (经典回放)If you are _______about the pyramids in Egypt, just read the book written by Dr. Brown.

A. anxious B. curious

C. serious D. puzzled

解析:本题考查形容词的区别。serious"严肃的；认真的"，与句意不符，一般也不与介词about连用；anxious与puzzled可与about搭配，但是前者表示"对......感到焦虑，担心"，后者则表示"对......迷惑不解"，通常表示对某一问题不懂，因而去寻求解答。因此be curious about"对......好奇"是最佳选项，相当于be interested in。

答案:B

归纳与迁移

(1)adj. 好奇的 

They stared at us in a friendly but curious way.

他们友好但是好奇地看着我们。

(2) be curious about sth. 对......好奇

She is too curious about her neighbour's business.

她太好管邻居的闲事。

(3)be curious to do sth. 好奇地去做某事

I am curious to know what will happen.