He _____ football regularly for many years when he was young.
A:was playing
B:has played
C:played
D:had played
对风的预报主要内容是风向和风级,下面对风向和风级的理解正确是( )
在昼夜交替现象的模拟实验中,手电筒代表太阳。
据考证,唐朝的《邸报》是世界上现在最古老的报纸之一,与该报的产生密切相关的科技发明是( )