英語文法問題

Has/ have/ had 后面都要放 past participle or present participle的。

past participle =verb normally ends with -ed/en
example: painted, taken, written, saved.

present participle = verb normally ends with -ing
example: thinking, waiting

若不大明白，可以去以下的网址，
在那里我有写更详细的例子。
http://hk.knowledge.yahoo.com/question/?qid=7007040602762
http://hk.knowledge.yahoo.com/question/?qid=7007040405018

你的例子:
i have just took a shower. （wrong, took=simple past tense)
I have just taken a shower.

i have just take a shower.（wrong, take= present tense)
I have just taken a shower.

Just = only 罢了
i have just taken a shower. (correct)
意思是指： 我刚刚才冲凉罢了。

I had taken a shower before I went to have dinner.
意思是我先冲凉，然后去吃晚餐。
（两件事都过去了，而且冲了凉还去了吃饭，
不用放just了，在此放just没意思。）

2007-04-10 20:22:05 補充：
I just took a shower.就可以。在此just = simply

We use 'just' when you want to express that you have already done something not long ago, and that action is already finished, so we use present perfect tense, so the answer should be:
b) I have just taken a shower.

I have just taken a shower.
or
I just took a shower.

上兩句既分別在於發生的時間
有Have 就要用taken

i have just taken a shower.