I Move Quickly
Physicists have built devices to make me move quickly. My last eight letters can be commonly found in newspapers, magazines, and journals.
What am I?
Particles. Physicists use particle accelerators and newspapers, magazines and journals have articles.
A Black Dog Sleeping
A black dog is sleeping in the middle of a black road that has no streetlights and there is no moon. A car coming down the road with its lights off steers around the dog. How did the driver know the dog was there?
It was daytime.
Remove Four And I’m The Same
I am an English word with five letters. If you remove my last four I am still pronounced the same. What am I?
Queue.
Favorite Pet is a Fish
I died and came back to life. My blood is not easily able to go through my body. My favorite pet is a fish. Who am I?
A shark. Sharks experience tonic immobility, also known as apparent death, where they appear to have died. Blood does not easily flow through their bodies, forcing sharks to swim continuously to circulate their blood. Lastly, sharks have pet fish called Remora (sometimes called suckerfish). They feed on parasites on the sharks and leftovers, and they use the shark as transport and protection.
A big thanks to Saravana for answering this.
Alone I’m Unknown
Alone I’m unknown,
With my twin I’m twenty,
And triplets make me a warning.
What am I?
The letter ‘X’. A single x is often used in math as an unknown, along with Mr. X. Two together (XX) make the Roman numeral 20, and three signifies a warning for adult only content, or a warning to other programmers of a problem in source code.
Together As One
I am word with six letters.
My motto is together as one.
If you remove my first and second letters, you can wear me.
If you remove my third letter I can be painful.
If you remove my second, third and sixth letters, Adam & Eve did it.
If you remove my second and third letters, you do this using your mouth.
What am I?
String. A string ties objects together. You wear a ring, a sting hurts, according to the Bible, Adam & Eve committed a sin and you sing with your mouth.
Celebrate, Hide Their Shame or Commit Crime
Some use me to celebrate,
Others use me to hide their shame,
Others use me to commit crime.
What am I?
Alcohol. People have a drink to celebrate, but also drink to hide their shame. Lastly, drunk driving is a crime.
A mask is also a valid answer. They can be used to celebrate Halloween or at dress-up parties, a mask can hide your shame and masks are used by thieves.
Update: This one has more valid answers than I thought. Money, drugs and night also work.
Three Foot Ruler
Where can you find a three foot ruler?
At a yard sale. How did another joke riddle get in here?