合同是双方的民事法律行为，合同的订立必须由当事人双方参加。( )
参考答案：对
He stood still in front of the shop window ______ he were thinking something.[ ]
A. as though
B. even though
C. as long as
D. although
句型转换。
This is my car. (改为一般疑问句并作肯定和否定回答)。
