问题补充:
On the table she found a piece of paper some confusing symbols.
A. which was written
B. that was written
C. on which were written
D. on that was written
答案:
A. which was written
B. that was written
(答案→)C. on which were written
D. on that was written
解析:从句可写成:some confusing symbols were written on the paper, 故用on which。