Question

几道高中英语选择题，知道答案求解析！

JIM is the first chinese from outside the US（ ）the donation project on sept 29 2010. A to join B to have joined C joined 这题是选择B 为什么呢 have joined 是现在完成时 那么前面加一个 to又是什么意思？？ 2 Have U ever been to BJ？ YES，I （ ）in BJ university for 2 years. A have studied B had studied C studied 这道题答案是C 老师的解释是说 C表示的动作已经结束 我选的是A 因为理解的是 过去对现在的影响 所以用现在完成时 3 Santa ，also （ ）as father christams，is A figure who is said to bring gifts to good children on christams eve. A knowing B known C being known 这道题是选择B，为什么呢？完全不懂 A C是怎么用的？

Answer 1

to是不定式的符号，这里面表目的 答句里面有个for，如果你要填现在完成时的话需要有一个since known as是固定搭配“被以为是”的意思