What does this below rebus puzzle mean?

What does this rebus mean?

O
N
C
E
TIME

Can you replace the question mark with the correct number in the below table sequence?

Different lights make me strange by changing me into different sizes. What am I?

People put me on the table and cut me but do not eat me. What am I?

A Doctor always sneezes before the rain. Doctor sneezes, Will it rain?

What word is represented by this rebus?

I’m orange, I wear a green hat and I sound like a parrot. What am I?

Suppose you are a girl candidate and sitting in an interview. Suddenly the interviewer asks you, 'What if one morning you wake up and find out that you are pregnant?

How will you reply to such a question?

Can you place six X (crosses) in below board without making three in a row in any way ?