He often plays football.他经常踢足球.
He was playing ball when his friends came.他朋友来时他正在踢足球.
描述一件正在进行(或某个时刻正在进行的事情)时,用进行时.
描述一件按一定频率(周期)发生的事情时用三单.
He often plays football.他经常踢足球.
He was playing ball when his friends came.他朋友来时他正在踢足球.
描述一件正在进行(或某个时刻正在进行的事情)时,用进行时.
描述一件按一定频率(周期)发生的事情时用三单.