Good Riddles

Question: There is a man who works on Big Bentley and he keeps the clock running smoothly. One day the clock stops all together, he muttered to himself "It's going to take me all day to fix it!" and he grumbles while he works because he doesn't want to have to change the time, but he finishes by tea and he doesn't have to change the clock by even a minute. How?

Question: Spelled one way it mows the lawn spelled another you put it on

Question: I can be one, I can be two. I can be Open, Closed, Empty or Full. I can be Bare, but never a Bear. What AM I??

Question: in all of written history I won't show up at the end of a sentence but I will be there in the end . . .

Question: A pond with dimension of 6m by 3m wil be filled of water lilies at exactly 30 days. Each day the number of water lilies will be doubled. First day 1, second day 2 etc... On what day it will fill half of the pond?