Have you ever seen a monkey in the forest before?
Yes, I have./No, I haven't.
Have you ever spoken to a stranger (陌生人) in English before?
Yes, I have. No, I haven't.
Where is the most beautiful place you have swum before?
The most beautiful place I have swum before is.....
Do you know anyone who has been to Egypt?
Yes, I know someone who has been to Egypt./No, I don't know anyone who has been.
Have you ever taught anyone something? What was it?
Yes, I have. I've taught someone to make cookies./No, I haven't.
Have you heard someone speak German before?
Yes, I have./No, I haven't.
Who has come to your house before?
Some friends have come to my house before.
How long have you known your best friend?
I've known my best friend for...../since....
Has your dad ever sung a song for you?
yes, he has. /No, he hasn't.
Have you written your homework yet?
Yes, I have written my homework./ No, I haven't written it all yet.
Have you ever fallen off your bike?
yes, I have./No, I have never fallen off my bike.
