A、 were B、 was C、 has been D、 had been
单项选择题The number of cell phones（）increased dramatically in the past few years.
A、 have B、 are C、 has D、 is
单项选择题you got Ul5 late won't be a sufficient excuse for your being late for class（）
A、 It is B、 That C、 Because D、 What
