如图是动、植物细胞结构模式图，据图回答：（示例：[⑥]细胞质）
— There's somebody at the door. Who ____ it be? Is it the postman?—No. It ______ be him. It's just seven o'clock. It's too early.
A big fire broke out last night. Luckily, the people in the burning house were ____(营救) by the firemen.
下列各句中，标点符号使用正确的一项是 ( )
