窗体顶端1:Be _ when holding those glasses; they are easy to break.1.cautious 2:He felt _ when he found he had difficulty with most of the math problem.4.frustrated 3:The machine can pull up trees as if they _ weeds (野草,杂草).1.were 4:I am _that he has not answered my letter.4.annoyed 5:One of my _ sentences is: There is no smoke without fire.4.favorite 6:The teacher _ everyone of his students will pass the exam