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． |
B． |
C． |
D． |
The achievements of the greatest minds in science could never have been reached________ the patient work of hundreds of others．
| A．were it not for | B．had it not been because |
| C．had it not been for | D．if it had not been |
The plans should be drawn as ________as possible，showing all the measurements．
| A．authentic | B．accurate | C．correct | D．proper |
In that south American country, _____bicycle is not_______ popular means of transportation．
| A．the；a | B．a；不填 | C．a：the | D．the；the |
The professor advised us to think outside the box and to________ new, different, or unusual solutions．
| A．put up with | B．come up with |
| C．keep up with | D．catch up with |
—Hi．Danny! Are you going for a picnic this weekend?
—I’m not sure._____________．
| A．It all depends | B．Yes．I’d like to |
| C．Sounds good | D．Sorry，I can’t |