People used to communicate on the phone， but now they are used __________on Wechat because it makes communication ________..

Let’s play ping-pong. —_________.

－Let’s go to the park tomorrow morning.－Sorry, I’ve got an important appointment at 9 o’clock and I can’t______to miss it. (济宁市)

The scientist is very modest. He never______.

_____–For tow hours.