由题意得：a-3a-5≥0且a-5≠0，
∴a＞5或a≤3．
故答案为：a＞5或a≤3．
I feel so tired, because there is________ homework to do and it’s ________hot today.
A．too many; too much
B．too much; much too
C．too many; many too
D．much too; too many
渗透泵型控释制剂常用的半透膜材料（）。
A．醋酸纤维素
B．乙醇
C．聚氧化乙烯（PEO）
D．氯化钠
E．1.5%CMC-Na溶液
