Question

ぽんぽん

答えは2なのですが、このinはどこから来たのでしょうか？

/〆                                82介入

(2) The seience of medienel (  ) progress has been

Very rapid Jateh   り1S perhaps the most important of
al sciences.         の

① for as     ② which
③ sincee     ④ so

(関西学院