He picked up an envelope ____50 dollars in it.
(2014届山东省济宁市曲阜师大附中高三上学期期中考试英语试卷) Some modem paintings are _____ my understanding; I simply can't understand what the painters really want to tell us.
David was always ______ his best in any danger, but at that moment he froze.
— Have our travel plans been decided?— No, still ______.
Math is ___________ me. I can never get high grades.
You may know better about Jack London if you have read a book_______ the name of The Call of the Wild.