Since the 1930s, hundreds of stone balls have been found in Costa Rica. It’s believed that they ______ by the ancestors of native peoples who lived there at the time of the Spanish conquest. 
(A)could have been made
(B)have been making
(C)could make
(D)being made

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統計： A(201), B(53), C(31), D(16), E(0) #418935

詳解 (共 2 筆)

#623485
20世紀30年代以來，已發現數百個石球在哥斯達黎加。它認為，它們可能是由原住民的祖先在西班牙征服的時候，誰住在這裡。
1
0
#732494
沒有省略should嗎
0
1