grammar 問題

(1)問題係點解do 同have 可以一齊用....2verbs??
Ans. Do is an auxiliary verb here. Have is the main verb.
(只有 have 是動詞，do 是助動詞)

(2) 我查過字典話do 做 Auxiliary Verb 噶話...一定係係否定句或者係係疑問句.......
Ans. This is not necessarily the case. Do can be used as an auxiliary verb in a positive statement.
(不一定，do 作為助動詞可用於肯定句中。)
Do is used to emphasize what you are saying when no other auxiliary verb is present.
(當句中並無其他助動詞，do 是用來強調其後的動詞)
Examples:
He did try his best in the exam. (他確有盡他最大努力。)
She does look tired. (她看來真的後累。)

(3)唔寫do 噶話ok 嗎??
Okay. The purpose of do is to emphasize the fact that traditional schools and teachers are still important today.
(唔寫do 是可以的，do 的作用是強調其後要講的話，直接用動詞便沒有強調的效果。)

(4)far more flexible 三個adj????
More flexible is the comparative form of flexible, just like bigger is the comparative form of big.
(more flexible 是 flexible 的比較式)

The word far in far more flexible is to emphasize the extent new mode of learning is more flexible than the traditional method.
(far more flexible 是要強調新教學模式遠較舊模式靈活)

You can also say a lot more flexible.

Please note the last word in your sentence should be era, not eva.