带式输送机分哪几种？
参考答案：
带式输送机按胶带选用情况分为普通带式输送机、钢绳芯带式输送机和钢绳牵引带式输送机；按托辊槽角分为TD62型和TD75型。
Your desk is crowded with too many unnecessary things，including used papers and books.You'd better ________ some of them.[ ]
A．remain
B．resist
C．remove
D．renew
十六烷值是（）的主要指标。
A.汽油
B.柴油
C.机油
D.液压油
