【单选题】— I called you yesterday evening, but no one answered. — I ______in my bedroom at that time.
【单选题】在操作系统中,( )是竞争和分配计算机系统资源的基本单位。
【单选题】— I called you yesterday evening, but no one answered. — I ______in my bedroom at that time.
【单选题】--I called you yesterday morning ,but no one answered. --Oh, I in my garden.
B.
am watering the flowers
C.
was watering the flowers
【单选题】调查几个重要铁路枢纽,就可以了解我国铁路货运量的基本情况和问题,这种调查属于( )。