I’m afraid our office is closed until nine o’clock tomorrow morning.  This sentence means our office will be open after nine o’clock tomorrow morning.

Could you charge it to my room? “charge” here means to add it to his account so he can pay for it later. 点击查看答案&解析

The important thing is that this is a major breakthrough. “breakthrough” here means an important development or achievement. 点击查看答案&解析