形容詞 unclear:

1. poorly stated or described
   同義詞：ill-defined
2. not clear to the mind
3. not easily deciphered
   同義詞：indecipherable, undecipherable, unreadable

1. The real cause of the riot is unclear, but the occasion is the arrest of two men.
   騷亂的真正原因不明，但起因是由于逮捕了兩名男子。
2. The real cause of the riot was unclear, but the occasion was the arrest of two men.
   騷亂的真正原因不明，但起因是由於逮捕了兩名男子。