“本年利润”账户年末可能是借方余额，也可能是贷方余额。（ ）
参考答案：对
It is very kind ______ you to help me with my lessons. It is difficult ______ me to learn them well. [ ]
A. of, of
B. for, of
C. of, for
D. for, for
弧形铸机铸坯中夹杂物有聚集现象，夹杂物聚集的位置（）。
A．离内弧表面约1/4厚度处
B．离外弧表面约1/4厚度处
C．铸坯厚度中心区
