I am glad you brought this up.

I googled some and found these:

https://www.bbc.co.uk/worldservice/learn ... v305.shtml
https://www.usingenglish.com/forum/ask-t ... -said.html

Thank for the link.

in the mgmat guide it uses "having + past participle" in two ways

(1) "having broken the lamp, she has been worrying all night"
(2) "having been shown into the office, julia waited for the dentist to arrive"

for #2 mgmat claims that "having been shown" is acting as a past perfect action, happening before "waited". I always thought past perfect was Had+ participle, but I know there is no "hadding", so i accept it.

then i see #1, so now "having broken" is a past perfect, whereas "has been" is in present perfect?

appears that "having + participle" somehow just assumes to occur prior to the tense of the subsequent clause. because in the link provided in the previous post, they use

"having + participle, then present tense in next clause"

any ideas?

having-past participle, here in example "Having broken the lamp, she has been worrying all the night"......having broken perform two actions, first! it tells that why she was worried whole night? because she broke the lamp. it modifies the whole clause second! she was worried after breaking the lamp, so to express an action that took place first and is completed we use Having-broken!! am i right?? i want an expert to comment here

If we want to emphasize that the action happens before the other one and both actions took place in the past, we can use having + V3 instead of a clause:

Having been beaten by Tyson, Geoffrey decided to give up boxing. (= After/As he had been beaten by Tyson, Geoffrey decided to give up boxing.)
Having written my letters, I did some gardening. (= When I had written my letters, I did some gardening.)

I have still not understood the difference here.

@ kasia!! it means i am clear in my concepts.. thanks for ur reply

Glad to hear that!