Referring to reading, we must have the patience to read ______ book so that we will have _______ deep understanding of it.
20. The rest of his life was devoted ___ pollution ___more happily .
19. --- Could you tell me how the sea sand comes about ? --- Sea waves dash against the rock. In this way , the sea sand ___ .
18. A new ___ bus service to Tianjin Airport started to operate two months ago .
17. Greatly moved by what he did , ____ .
16. My dear , where have you ___? I___ you everywhere .