2. 用插入语开头，表示说话人的态度，或使句子的意思更加准确：

Strangely enough, Jennifer does not enjoy sunshine and beach.

Generally speaking, winter in Vancouver is gloomy.

类似的插入语有：

no wonder no doubt

in other words in my opinion

in conclusion in fact

as a matter of fact　

3. 用形容词、并列形容词或形容词短语开头，修饰句子的主语，表示主语的特征或状态：

Frantic, the young mother rushed out the door with the baby in her arms.

Tasty and crisp,potato chip are a favorite snack for both children and adults.

Happy at his good marks at school, the little boy skipped on his way home.

Desperete and hopeless, the poor man committed suicide.

4.用分词、分词短语开头：

（a)修饰句子主语，表示主语所处的状态或主语同时进行的另一个较谓语动词次要的动作：

Scared, the girl moved timidly and cautiously into the dark room.(状态）

Cgased by my dear pet cat, the mouse dashed into a snall hole.(状态)

Spoiled by his parents, the naughty boy always insists on things he wants.(状态）

Puffing and hugging, he finished his run.(另一动作）

Looking at herself in the mirror, she fingered her silk scarf on her shoulder.(另一动作）

(b) 修饰谓语动词，表示原因、时间等

Lying down on the couch, he felt much relaxed.(时间）

Feeling bored, she turned on the TV and switched from channel to channel.(原因）

Wanting to find out the business hour,she called the store.(原因）

Having completed the form, dhe mailed it out immediately.(时间）