问题
选择题
What happens _____ trees in the different seasons? [ ]
A. in
B. on
C. at
D. to
答案
答案：D
搜题请搜索小程序“爱下问搜题”
What happens _____ trees in the different seasons? [ ]
A. in
B. on
C. at
D. to
答案：D
缺失，拟行可摘局部义齿修复，
做基牙，采用弯制卡环，卡环制作时下列哪一项是错误的（）。