参考答案

正确答案：A
解析：本题考查倒装句。“not until”意为“直到……才……”。置于句首进行强调时，主句应发生部分倒装。再根据"recently"来判断，动词应该用过去时，所以选择A。此句的强调句型也可变成另一种形式：It was not until quite recently that I had any idea of what a guided rocket is like。