通常需要抗弯能力强的材料来建造的桥梁是（）。
参考答案：梁式桥
Though__ __ came that he was completely defeated, he didn't lose ______.
A．the word; his heart
B．the word; heart
C．word; his heart
D．word; heart
在分裂间期呈现着色较深的异染色质状态的失活X染色体，也叫作（）。
