2cos60°的值是（　　）

写作内容：1)．时间是3月10日(星期六)晚上6：30；

2)．地点是学校操场；

3)．内容：  (1)表演：英语戏剧、英语歌曲；(2)英语游戏、与外教交流。

注意事项：1)．请有表演(perform)节目的同学做好准备：

2)．准时参加。

写作要求：1)．80词左右；

2)．信中不能出现真实姓名与学校名称。

An English Evening

    Jenny is Mr. White's little daughter. She is good at Art . But she isn't good at Math. Mr. White is teaching her ,”What's six plus three?”

    Jenny counts her fingers and answers ,”It's nine .”

    “Good .What's twenty minus three?”

    Anna counts her fingers and toes. “Mm.it's five .No , it's seventeen .”Jenny answers slowly.

    “What's eleven plus twelve, then ?”Jenny looks at her fingers and toes . They are not enough (足够). Seeing this , Mr. White isn't glad and says, “Use your head, Jenny .”

    “That's not enough .I've got only one head.”

根据短文内容，判断下列句子是否正确。