english Grammar

樓上理解錯了。呢句其實可以咁分析：
all this heavy workload does is teach children that school is boring.
咁分開佢，呢句其實只係一個簡單o既 subject + verb + complement o既結構，好似 I am fine 一樣。
睇 subject 先。The Beatles 有隻名曲叫 All you need is love，當中 "all you need" 就係 subject，雖然呢度句含左一個動詞，但只係成個主詞o既一部份。情況好似 relative clause 之中o既動詞一樣。
至於 complement，其實一般情況，我地都會用 to-infinitive clause 去寫，以我自己o黎講，就會偏好：
Sadly, all this heavy workload does is TO teach children that school is boring.
但其實將 to 省略亦無不可。所以你引o既例句亦無問題。
－　－　－　－　－　－　－　－　－
跟據以上原則，以上你補充o既兩句文法冇問題。

(A) "The program is teach children that life is precious."
(B) "The program is to teach children that life is precious."

Which one is correct?

The words "does is teach" seem to be "three verbs". However, if reviewing the whole sentence, it is NOT.

1) "Does" in this sentence is to emphasize the meaning. For example, I do need money for holidays = I really need money for holidays. 我"真的"很需要渡假. Since workload is "single", it uses "does" rather than "do"

2) is the main verb
3) teach is infinitive without "to"

Thus, the sentence may be written as "Sadly, all this heavy workload really is to teach children that school is boring".

Hope this helps.