在下面句子的空白处填入一个适当的词，使句子意思完整、语法正确
It's a waste to cutlots of trees for chopsticks every year.
本题考查 cut down 的固定搭配。句意：每年都砍伐许多树做筷子，真是一种浪费。cut down 意为 “砍伐；砍倒”，故所缺的词是 down。
The students of Grade Eight _____ reading 9 exciting mystery stories so far.
根据so far 可知要用现在完成时，故答案为选项B。
—If you like the phone,you'd better buy it.
—But it's too expensive. I can't _____ it.
词义辨析。
根据本题语境可知，那个手机太贵了，我负担不起，故所缺的词是afford，afford可以搭配afford to do；pay可以搭配pay for；provide可以搭配provide sb. with sth./ provide sth. for sb.