4. I don't understand what the engineer means, but I've got ______ rough idea of ______ project plan.
A. the; a   B. /; the   C. the; /   D. a; the
4. D。句意：我不明白那位工程师的意思, 但我已大致了解这个项目计划。have a rough idea是固定短语“大致了解”, 而plan在本句中表特指, 故用the。