一個句子只出現一個"as" 它怎樣有"比較"的意思?(10分

That dish is delicious, and this one is just 「as」 good.

1)這裡是怎樣地比較??

這是先後比較，先說了一樣東西，然後說第二樣東西和它比較。
That dish is delicious, but this one is not as good.
That dish is declicious, and this one is almost as good.
That dish is delicious, and this one is just as good, if not better..

另一位答者說的 "that dish is good, as is this one'，的確不是比較，而是解 "same as"，但和以上句子不同。以上的 "as", 可以寫成 as good, not as good, almost as good .... 等，作不同程度的比較。
2)而且寫作時如何會用到as (比較) 在句子中??
例如應該放在句子的那個位置
又或者個as放係那個詞性的前後 以及該意思
就例如 as good 是什麼意思呢?/

因為是比較，所以 "as" 通常放在形容詞或副詞之前：
e.g.
She is very accommodating, whereas her mother is not as kind. (adjective).
He runs like a rocket; I can never run as fast. (adverb).

在用 as opposed to 這個 idiom 時，as 是放在 past participle 前面。

"as good" = equally good.
e.g. That dish is delicious, and this dish is eqully good.

3)最後as...as 同 as 都有比較的意思
但有分別嗎

有。 "That dish is delicious, and this one is just 「as」 good". 是先後比較。 "This dish is as delicious as that one" 是同時比較，只須要用 delicious 一個形容詞。而先後比較要用兩次 adjective。
意思方面，我覺得是差不多。

我推薦您一個非常不錯的英語學習網站，里面有很多非常不錯的學習資源：

http://www.hkenglishstudy.info

希望可以幫到你!

That dish is good, and this one is just as good.
= that dish is good, as is this one
In the sentence, "as" (就如/正如/如同) is used to make a commentor to add information about what you have just said.作評論, 或補充剛說的資料 。e.g. She is very tall, as is her mother.
= She is very tall, and her mother is just as tall.
先說 She is very tall, 然後補充資料:正如她媽媽也很高。

用法不同as.....as
as....as (comparison比較)
She is as tall as her mother=她和她媽媽的高度一樣。

其實用一個定兩個AS都係一樣意思都係比較. 但寫法上有少許分別.

That dish (A) is delicious, and this one (dish B) is just 「as」 good.
呢句用一個AS有指 Dish B 都係同 DISH A一樣咁好味. 但呢句用JUST AS有同級數既意思.

如果用兩個AS. 即AS乜AS乜呢.
例如:

That dish is as good as this one.
那味食送真是同呢味都一樣咁好味.