“do”有兩種詞性：1. 實意動詞（表示有實際動作含義的詞），理解成“做，幹”，如do your homework. Just do it... 這部分是容易理解掌握的；2. 助動詞，輔助其他實意動詞構成謂語，因為漢語中基本沒有這種語言現象，英漢明顯差異造成瞭部分學生很難理解掌握“助動詞do”及其衍生詞（don't/does/doesn't）的用法，所以需要重點闡釋說明。

可以先朗讀記憶語法部分的例句，形成初步感性印象：

1. Do you have a baseball? Yes, I do./No, I don't. I have a volleyball.
2. Do you have a ping-pong bat? Yes, I do./No, I don't. I have a ping-pong ball.
3. Does she have a tennis ball? Yes, she does./No, she doesn't. She has a baseball.
4. Does he have a soccer ball? Yes, he does./No, he doesn't. He has two ping-pong bats.
5. Do they have a basketball? Yes, they do./No, they don't. They have a volleyball.

歪理邪說

助動詞do扮演的很像是大地主傢小丫鬟的角色——“無名無姓，吃苦受罪”：

1. 所謂“無名無姓”，是指助動詞do沒有實際意思，或者說是根據不同的情況會有不同的意思，如：

Do you have a baseball? Yes, I do./No, I don't. 中的“do”和“don't”可以分別理解成“有/沒有”；

Do you play volleyball? Yes, I do./No, I don't中的“do”和“don't”可以分別理解成“打/不打”；

Do you like soccer? Yes, I do./No, I don't. 中的“do/don't”分別理解成“喜歡/不喜歡”。正如丫鬟並不需要真實姓名，完全根據主人喜好“起名”。

2. 所謂“吃苦受罪”，是指助動詞do在變疑問，變否定，肯定/否定回答中扮演瞭“吃苦受罪”的角色，變成does/don't/doesn't。如：

You have a ping-pong bat. 變成疑問句，隻需要讓Do打頭，句號變問號即可：Do you have a ping-pong bat? ；

主語三單形式時：She has a baseball. 變成問句時把Do變成三單形式Dose，而不需變化其他：Does she have a baseball?；

而在進行“否定變化”時，do/does需要與最不受“待見”的not連接表示否定變化：

They have a basketball. 變成They don't have a basketball.

He has a volleyball.變成He doesn't have a basketball.

課堂課後練習：

（略）