Logic Riddles

Question: A person has one lion, one lamb and a bundle of grass. He wants to cross a river but there is only one boat and it can't sustain the weight of more than two articles at time. Also, he has to make sure that the lion doesn't eat the lamb and the lamb doesn't eat the grass. How will he get to the other side of the river with all three intact?

Question: What is the only question you can't answer yes to?

Question: I'm teary-eyed but never cry.
Silver-tongued, but never lie.
Double-winged, but never fly.
Air-cooled, but never dry.

What am I?

Question: In a marble hall as white as milk, Lined with skin as soft as silk, Within a fountain crystal clear, A golden orb does appear, There are no doors to this stronghold, Yet thieves break in and steal the gold. What am I?

Question: You create your own Where's Waldo game on a piece of paper. You want your friend to find Waldo but they think you might be pulling a prank on them by not putting Waldo on the paper at all.

How can you prove to your friend that Waldo is on the paper without ruining it for them?