英語語法關於詞性問題

1. Our test results have been doubtful (adjective)!
1. There has been doubt (noun) about our test results!
1. Other people doubt (verb) about our test results!

2. F5.beat F6 dramatically (adverb) in the basketball match.
2. The last minute score in the basketball match earned F5 a dramatic (adjective) victory over F6.

形容詞是顯示事物或動植物性質特徵, 通常安置所修飾的 noun前面或者連結動詞 (linking verb) 後面. 有時在 noun 後面

I saw a beautiful girl. (在 girl 前面)
The girl was beautiful. (在 was 後面)
I found the girl beautiful. (在 girl 後面)
Beautiful 是形容 girl.

副詞是顯示動作特徵和動作進行中各種狀況. 可表示時間, 地方, 方式, 程度等概念
副詞可修飾動詞, 形容詞, 其他的副詞及全句子
He runs quickly. (副詞修飾動詞)
The homework is extremely difficult. (副詞修飾形容詞)
He runs very quickly.. (副詞 very 修飾副詞 quickly)

上述只是形容詞和副詞最基本區別. 詳情參考 grammar textbook
兩者最大分別副詞可有可無,沒有了仍然是一完整句子
形容詞有時可無, 但有時是必要的.
形容詞效用是修飾名詞, 副詞不可能修飾名詞
The girl was (beautiful) ~ 不可能刪除形容詞
I saw a (beautiful) girl. ~ 可刪除形容詞
He runs (quickly.) ~可刪除副詞

It is advisable to learn different patterns of sentence structure. For example,

It is + adjective + that .....e.g. It is good that ...
It is + adverb + adjective + that ... e.g. It is terribly bad that ...
subject + transitive verb + object + adverb e.g. He ate the apple quickly.
and many more...

1. doubt is verb
when you decide that whether using 動詞,副詞,形容詞
try to understand the sentence
1.Our test results have been doubtful good!Almost all of us passed the test.
Other people will doubt about our test result
so it is doubtful good to other people
you may also consider that if it is verd,then adj, that adverb

2. dramatically is an adverb
F5.beat F.6(dramatically) in the basketball match.No one had expected such a result before the match.
It is dramatic that F5 beat F6
so F5 beat F6 dramatically