关于细菌L型，下列哪一项是错误的()

A．细菌L型是遗传性变异的细菌

B．细菌L型是细菌失去细胞壁所形成的细胞壁缺陷型

C．细胞壁的缺陷主要是肽聚糖的缺陷

D．细菌L型在脱离诱导剂后可回复为原来的细菌

E．凡能破坏肽聚糖结构或抑制其合成的物质都能导致细菌L型的形成

The Internet celebrated its birthday on September 2nd, by which time 40 years _______ since the first successful transfer of data between two computers.

A．has passed

B．had passed

C．passed

D．have passed