题目

Beijing National Stadium，the showpiece of the Beijing Olympics，has fallen into disuse since the end of the games，_________it difficult to make a profitA．make                             B．to make             C．making                      D．made  答案：C8．下列关于鲫鱼体内的核酸彻底水解后，所得到的物质正确的是（　　）A．有1种五碳糖B．有4种脱氧核糖核苷酸C．有5种含氮碱基D．8种核苷酸