A-A+
The Bunsen burner is so named because it is th
问题详情
The Bunsen burner is so named because it is thought ______ by Robert Bunsen, who was German by birth.
A．having been invented
B．to be invented
C．to have been invented
D．being invented
参考答案
正确答案：C
解析：本句是It is thought that．．．这一句型的变体。由于不定式的动作发生在“It is thought…”之前，因此不定式采用完成式。另外，这里的“让”指代“The Bunsen burner”而不是充当形式主语。
