Which is the rope you never skip with?

What common phrase is represented by the below lines

Easy going:
Weak, 'I'm going.'
Tough, 'I'm staying.'

Medium going:
Weak, 'I'm going.'
Tough, 'I'm staying.'

Tough going:
Weak, 'I can't do it, I'm staying!'
Tough, 'Let's get going.'

When I go in I might cause pain. I cause you to spit and ask you not to swallow. I can fill your hole. What am I?

Can you write down eight eights so that they add up to one thousand?

If your uncle’s sister is not your aunt, what relation is she to you?

I am a type of room you cannot enter or leave. Raised from the ground below, I could be poisonous or a delicious treat. What am I?

Rebus Puzzle Definition: A rebus is an illusion device that uses pictures to represent words or parts of words.
What does This Rebus Puzzle Identify?

What will be the best approach to finding all the prime numbers less than 75 that leave an odd reminder when we divide them with 5?

Why is a river so rich ?

I am a mother. However, I never give birth.

I am a father. However, I never nurse my children.

Wandering is not possible for me, but standing still happens occurs rarely.

Who am I?