杆件失去了稳定性主要原因是强度不足引起的。( )
参考答案：错
Though buried in the ruins for about 70 hours after the earthquake, with great luck, the man managed to______.
A．recover
B．exist
C．survive
D．rescue
明清之际的思想批判包含有哪些内容？各具有哪些进步意义？
________________________________________________________________________________
