一句簡單的英語句子出現了錯誤，何以題目說的這麼大？
故事是這樣的，近日筆者看到一份小學生英語期末考試答卷，其作文中的英語句子出現了明顯錯誤，老師發現了，並且用紅筆修改成了自認為合適的句子。筆者將其錯誤句子和老師修改後的句子發到悟空問答上，發到某中學英語老師的群中，結果有熱心老師做出了回答，部分老師的答案卻讓人不敢苟同。現將原題顯現如下，供大家討論。筆者之所以言稱母語影響，提及暴露功底，不是譁眾取寵，而是有感而發，並且會在下面具體的論述中談及，請繼續閱讀。
小學生寫的英語原句是：His favorite sport is play basketball. 凡是中學畢業的，應該都理解哪裡出了問題，兩個動詞或者說一個系動詞和一個原形動詞放在了一個句子裡，這當然是不符合英語語法的。但為什麼小學生會寫成這個樣子？這和漢語中的語言次序語言思維是一模一樣的。漢語中是：他最喜歡的運動是打籃球。請注意打字以及打籃球，都可以用play basketball表達，而小學生學過大量的my favorite food is 什麼什麼類似的句子，這個句型已經深入人心。所以，在學生看來，句子是順理成章的，甚至是完美的。問題就出在這個play上，因為我們國人都用打籃球表達。這是非常符合漢語思維的，如果說，將打籃球翻譯成play basketball應該沒有什麼問題，但是要是放到前面整個句子中，就出現了問題，就不符合英語思維了。這個待會大家會看到說明，按下不表。
而英語老師在看卷時，順手將句子改成了 His favorite sport is playing basketball. 估計感覺這麼改是成功的，並且僅僅增加了ing而已。對這句話，喜歡語法的人往往會做出兩個解釋，要麼是進行時態，要麼死系表結構，在我得到的回答中，他們貌似也很自信，認為這個改動是正確的。其實這恰恰反映了我們國內學習英語的現狀，大家都以為語法是學習英語的重要部分，而對中英文的表達結構不太注意，並且動不動使用語法來分析句子，而缺乏用其他角度看待這些句子問題。
那麼具體是錯在哪裡了？讓我們看看一位老外的回答吧。注意，裡面的運動換成了足球而已。另外，我在關鍵的地方稍微翻譯了一下。
Does my favourite sport is play football grammatically correct （語法正確）? Or my favourite sport is playing football.
My favorite sport is play football" is ungrammatical（不符合語法）. You would have to put the verb "play" in its progressive form so it would work with "is" to result （結果）in "My favorite sport is playing football." But that's not really a present progressive（現在進行時）—your sport cannot play! Therefore "playing" can only go in as a gerund（動名詞）, the noun form "playing." In any event, "my favorite sport is playing football," while grammatical, is not as likely a thing for someone to say as a more natural way to put it. （就是說增加了ing後並不是合適的語言）
he more natural formulation (at least in American English) would be to say "My favorite sport is football." Why? It gets a little subtle（微妙，不易察覺）. After all, we do "play sports." Someone can "play tennis" like a pro（老手）, or "play golf" like a total buffoon（小丑）—you don't even have to be good at it to say you are playing a sport! So let's pull that sentence apart.
The subject is "sport." "Sport" is a noun in this case. Then you need a verb. We have "be" and "play" as possibilities. Then you have a complement（理解成補充吧）—the part following the verb to finish the sentence. That part is the noun "football." So your basic sentence—the core of it—comes down to "Sport-VERB-Football."
"Sport is football" is good as the basic structure (you need to add the modifiers before "sport" of course. You have the verb "is" as a copula（系動詞） that links "sport" and "football."
But what about "play"? Could you say * "Sport plays football"? No. What if you add in those modifiers and say * "My favorite sport plays football." No, that doesn't work either. It is not ungrammatical—but it semantically（語義上） unworkable—sports cannot play sports. So if you want to have "play" in there, your only option is to use the -ing form "playing" to get "My favorite sport is playing football." But as noted above, "playing" is not a verb—it must a noun, a gerund to be specific. And I would say "sport is playing" is wordy（囉嗦的）. What do you do with a sport? You play it! So the concept of "sport" already includes the idea of playing so it is wordy. So we are back to "My favorite sport is football" as the best option. 黑體是最合適的改法。
Note the difference in what "playing" means in the following two sentences.
First playing: "My favorite sport is playing football" versus Second playing: "My favorite son is playing football."
he first "playing" is a gerund, a noun, and the second one is a verb and is part of the present progressive "is playing."
後面這些對多數人有些難了，可以直接跳過，因為屬於補充，另外這篇文章非常適合高中生和英語老師們閱讀，當我們遇到英語問題時，最好的辦法就是尋求母語為英語人士的答案。
The first "playing" refers to a preference（偏好） for football that is not bound by time—that preference presumably emerged （大概出現） in the past, still exists now, and will continue to exist. The second "playing" could refer to an action taking place right at the time ("You want to talk to Johnny? My favorite son is playing football in the park—you can find him there") or it can also be relatively unbound by time ("My favorite son is playing football for the Patriots!"—where "is playing" refers to a contracted period and not the immediate moment).
Conclusion and ambiguity
The most typical and natural expression would be "My favorite sport is football."
But! It's still ambiguous! Does it mean football is your favorite sport to watch on TV? Or does it mean it is your favorite sport to play? If you want to make it clear that you are saying that you yourself like to play football, how do you get the idea of "play" back in the sentence—especially since "My favorite sport is playing football" feels a little wordy or redundant?
Well, in that case you could live with "My favorite sport is playing football—I don't just like to watch it." Or you could go with "My favorite activity is playing football." Or something along those lines.
The point here is that even a superficially simple statement like "My favorite sport is football" can still be read with different meanings and implication. Those differences are usually sorted out in context. So if you are writing such potentially ambiguous sentences, you have to take care to provide the reader with enough context so the intended meaning gets across.
See how little context needs to be added to change the meaning even with the first sentences being identical:
"My favorite sport is football. I've been playing it since I was 9!" (You play, but you may or may not watch it.)
"My favorite sport is football. I don't watch anything else on TV!" (You watch it, but you may or may not play.)
如果你整體看下來，相信你會同意我的表述，那就是：
小學生英語造句彰顯母語影響，老師們修改句子暴露英語功底
