下列计算正确的是 [ ]
A.3a+3b=6ab
B.3m﹣2n=1
C.2y+5y+y=7y
D.﹣3a+3a=0
答案:D
Mrs ,Taylor has ___8-year-old daughter who has _____gift for painting –she has won two national prizes.
A.a,a
B.an,the
C.an,a
D.the,a
当总需求不足时,应增加货币供应量。( )