----Do you know_____ second-hand smoke? ----To prevent our health and memory.
A.how we should prevent | B.how we should prevent |
C.why we should prevent | D.whether we should prevent |
----Do you know_____ second-hand smoke? ----To prevent our health and memory.
A.how we should prevent | B.how we should prevent |
C.why we should prevent | D.whether we should prevent |