一个四棱锥和一个三棱锥恰好可以拼接成一个三棱柱.这个四棱锥的底面为正方形,且底面边长与各侧棱长相等,这个三棱锥的底面边长与各侧棱长也都相等.设四棱锥、三棱锥、三棱柱的高分别为,,,则( )
A red light will start continuously flashing when the batteries____ low.
I’m sorry I didn’t phone you, but I’ve been very busy_____ the past couple of weeks.
The science of computer,____ rapid progress has been made, is the most important of all.
Before use, your new mobile must fully____.
—Remember not to pretend to know what you don’t know. — _____. My last lesson is still fresh.