“流连戏蝶时时舞，自在娇莺恰恰啼”、“稻花香里说丰年，听取蛙声一片”古人留下的诗句给我们带来了美的享受，也蕴含了许多生物学知识。请利用所学知识回答下列问题。
用NA表示阿伏加德罗常数的值。下列说法正确的是
There were two students in the class buildings during the earthquake, but of them failed to run out.
