粒级煤是煤炭的一个品种。
参考答案：对
With international ______ and education exchanges increasing every year, the number of Chinese students studying abroad has increased rapidly.
A．cooperation
B．competition
C．construction
D．conflict
《商标法》规定的注册商标有效期为（）年。
A.3
B.5
C.10
D.20
