亦是挑錯 - 自學

1. We had realized the error earlier, immediate restitution could have been
---------------a ---------------------a
taken, and the chaos that unfortunately followed would have been avoided.
----------------------------c -----------------------d



請問答案為什麼是a呢？

2. These are among the most popular products on the market is a well-known
-----a --------b --c
fact, and we believe that they will continue to be populare for some years
----d
to come.




請問答案a要改成什麼才是對的？

麻煩諸位大哥大姐了，謝謝。


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