  This paper is a Reply paper to the Comment paper by Mondaini et.al.
[arXiv:1711.06279]. We first distinguish the diagonal and the off-diagonal
eigenstate thermalization hypothesis (ETH) in each sector and in the whole
Hilbert space, and then clarify their properties and their roles in
thermalization. We argue that our formulation of the ETH in our letter is a
standard and natural one in the context of thermalization, and that our results
are qualitatively new and unexpected.
