1.Our teacher said n______ and went back to his office.

1.Our teacher said n______ and went back to his office.
2.Welcome ______ home.
A.to B.from C.back D.at
3.Jim is looking for his cat _______.
A.somewhere B.anywhere C.nowhere D.everywhere
4.I can't decide ____.
A.what to do when to do C.how to do D.where to do