= A boy went missing, and the police were puzzled.

missing 和puzzled分别为现在分词和过去分词作表语。现在分词作表语和主语之间往往是主动关系，表示主语的性质；过去分词作表语和主语之间往往是被动关系，表示主语所处的状态.

(1) 消息很激动人心，所以听到这个消息学生们都很激动。

(2) 我们被那只吓人的老虎吓住了。

2. ... who went missing two days ago

go (+adj.)　Link. v 变得...(往往由好变坏)

His hair has ＿＿＿＿＿＿＿＿＿(变得花白) over the years.

We can't let the child ＿＿＿＿＿＿(挨饿).

She ＿＿＿＿＿＿＿＿(发疯)when she found out that she had failed the exam.

3. show (an) interest in

　have an/no interest in

　take （no） interest in

　feel no/much interest in

　develop (one's) interest in

　lose interest (in)

4.However, police found that Justin did

in fact return...

do, does和did分别用于一般现在时和一般过去时

的肯定陈述句中,与动词原形连用,用以加强语气,在

句中要重读.

If you do find the book, send it to me.

Do write to me soon!

He does know where the man is hidden.

注意:用以强调句中的主语,宾语和状语的,要用

"It is/was ... that (who) ..."

She saw a thief in the shop this morning.