62. _____ you are permitted to speak, you have to keep silent in the meeting.
(A) If
(B) Unless
(C) Because
(D) Since

 Unless(除非) you are permitted to speak, you have to keep silent in the meeting. 

除非你被准許說話，不然你在會議中應該安靜。

主要子句不需要加上”or”，避免一個句子同時出現兩個連接詞。
→ Unless Andy makes lots of money, or Mary won’t marry him. (X)

Unless + S + 肯V, ___________.
= If + S + not + 肯V, _________. Unless Andy makes lots  of money, Mary won’t marry him.
= If Andy doesn’t make lots of money, Mary won’t marry him.
除非Andy賺大錢，否則Mary不會嫁給他。

https://tw.blog.voicetube.com/archives/19296 

【秒殺文法】中英邏輯大不同：「除非」你都會？一次搞懂Unless的用法！

這句是不是可以改成：Unless you are permitted to speak or you have to keep silent in the meeting.
???