Seniors need to increase their water intake and______(有规律地参加身体锻炼).

A．being a main competitor of RosettaStone
B．by which users can chat online with natives
C．including traditional lesson-based module
D．by which users can play games related to language

A．She hasn’t heard from the teacher for three days.
B．They have extra time to complete the assignment.
C．She just found out the medical paper three days ago.
D．They won’t see the teacher until three days later.