如果(m+3)x2-mx+1=0是一元二次方程，则 ( )
A：m≠-3
B：m≠3
C：m≠0
D：m≠-3且m≠0
如果m是任意实数，则点P(m-4，m+1)一定不在（ ）
Mary's grandpa is always ______ in the mountain village. He tells her he feels very______. So she's going to visit him next week.
下列各句中，没有语病且句意明确的一句是( )
