3 houses

Question: there are 3 houses. a brown house a green house and white house. if the green house is in front of the brown house. and the brown house is in the back of the green house, Where is the white house?

Question: During what month do people sleep the least?

Question: When is 99 more than 100?

Question: People see through me, but none pass through without killing me. I can be anywhere, and can be seen double or single. What am I?

Question: What are the next two letters in the following series and why? WATNTLITFS__

Question: Surrounded by life , yet life is its biggest enemy. But without life there is no need for it to exist. What is it?