What is Active Voice? 甚麼是「主動語態」?

In a sentence, there are often the "subject", the "verb" and the "object". Normally the subject is before a verb, and the object is after a verb.
在一個句子裡,通常會有主語 (subject)、動詞 (verb) 和賓語 (object)。
For example 例如:
My mother cooks our dinners.
("My mother" is the subject, "cooks" is the verb, and "our dinners" is the object.)
(My mother是主語, cooks是動詞, dinners是賓語。)
The verb in this sentence is in "active voice".
在這個句子中的動詞是用「主動語態」(active voice)。

What is Passive Voice? 甚麼是「被動語態」?

Sometimes, we hope to emphasize the "object" in the sentence and we can put the "object" before the "verb", and the "subject" after the "verb". We will also change the tense of the verb in "passive voice".
有時候,我們希望強調句子裡的賓語 (object), 我們便會把賓語 (object) 放在動詞前面,而主語 (subject) 放在動詞後。這時我們亦需把動詞轉做「被動語態」 (passive voice)。

For example 例如:
Our dinners are cooked by my mother.
The object "our dinners" comes before the verb "are cooked" which is in passive form. We also use the word "by" after the verb.
句子中的賓詞 "our dinners" 放在動詞 are cooked (被動語態) 的前面。同時,我們可以在動詞後加上 "by" 這個字。)

How to change a verb into passive form? 如何把一個動詞轉為被動語態?
verb >> be + past participle of the verb
(動詞 >> be + 動詞的過去分詞)

Different tenses of verbs have different "passive" forms. Let's look at the examples below:
不同時態的動詞有不同款式的「被動語態」(passive voice),看看以下例子:

(a) Simple Present Tense (簡單現在式)
am taken
is taken
are taken

(b) Simple Past Tense (簡單過去式)
was bought
were bought

(c) Simple Future Tense (簡單未來式)
shall be bought
will be bought

(d) Present Continuous Tense (現在進行式)
am being taught
is being taught
are being taught

(e) Past Continuous Tense (過去進行式)
was being taught
were being taught

(f) Present Perfect Tense (現在完成式)
has been taught
have been taught

(g) Past Perfect Tense (過去完成式)
had been taught

Changing the sentence in "active voice" to "passive voice":

The robbers attacked Mr. Chung.
Mr. Chung was attacked by the robbers.

I will buy the big calculator tomorrow.
The big calculator will be bought by me tomorrow.

We find the new dictionary.
The new dictionary is found by us.

My little sister is drawing the beautiful picture.
The beautiful picture is being drawn by my little sister.

Mum washes the clothes every day.
The clothes are washed every day.

The thief has stolen the wallet of the rich man.
The wallet of the rich man has been stolen by the thief.

Tom makes that toy car.
Is that toy car made by Tom?
Which toy car is made by Tom?

I will send this card to my friend tomorrow.
Will this card be sent tomorrow?
Which card will be sent to your friend tomorrow?