A、A. We should lower national flag when the sun sets. B、B. We should lower national flag when the ship is in port. C、C. We should lower national flag when loading and unloading. D、D. We should lower national flag when the sun rises.
A、A. We should lower national flag when the sun sets. B、B. We should lower national flag when the ship is in port. C、C. We should lower national flag when loading and unloading. D、D. We should lower national flag when the sun rises.
A、A. When we are playing basketball. B、B. When we are making a speech. C、C. When we are having a party. D、D. When we are talking with somebody.
A、When attacking the fire directly B、When using a steam smothering system C、When using the fixed CO2 system D、All of the above
A、the distance between them remains the same B、the distance between them is changing C、the position between them is not changing D、their positions to the earth remain the same