在一定时间内，某生态系统中全部生产者固定的能量值为a，全部消费者所获得的能量值为b，全部分解者所获得的能量值为c，则a、b、c之间的关系是[ ]

A．a=b+c

B．a>b+c

C．a<b+c

D．c=a+b

Without my glasses, I couldn't _______ whether that figure on the blackboard was a three or an eight.[      ]

A. make out    

B. make up    

C. make for      

D. make off