—Will you please tell us how you can seize the robbers?
—I will spend a whole week ________in your room to wait for their coming.
A：locking
B：to lock
C：locked
D：being locked
如图所示的做法中，符合安全用电原则的是（ ）
600÷3=____
160÷40=____
23×30=____
50×12=____
