balanced ventilation system

the two of them could not speak at the same time.

话机两边的人不能同时讲话。

Well, they can speak Mandarin at home and when they meet and mingle with their friends and others; How she manages to tear around from one social function to another and take care of her family at the same time is more than I can understand.

在家庭、社交场合、公共场所以华语与人沟通；我真不明白，她怎么能够从一个社交场合到另一个社交场合，忙个不停，同时又能照料好家务。

don't all try to speak at the same time when you are in a group.

当你们是一组人时，不要在同一时间说话。

don't all speak at the same time.

大家别同时说话。

At the same time in my professional life, someone did speak up

而在我的职业生涯中确实有人无保留地说了出来

All speak at the same time.

大家同时说.

a home with a balanced ventilation system with approximately neutral indoor air pressure is safer, more comfortable, and more efficient.

一所住宅使用中性室内空气压力平衡通风系统，更安全，更舒适，更高效。