Question

-----in 1788,the thirteen original states worked together un

Answer 1

答案是C.

Adopted by the Constitution是分词结构,可以说是做定语成分,做前置定语,修饰the 13 original states,等於：the thirteen original states,which were adopted by the Constitution in 1788 ,worked together under an agreement called the Articles.

A 的话,要倒装：did the 13 original states work -- - -

B 的话,需要加上连接词：The Constitution was adopted in 1788,the thirteen ,and the 13 - - - .D的话,句子结构是：Until- -- ,the 13 original states DIDN'T work -- -- .