由于沿程阻力做功而引起的水头损失则称为沿程水头损失（）
参考答案：对
There ______ mutton and dumplings on the table, but I don't feel hungry. [ ]
A. has
B. is
C. was
D. were
制作凉皮的调料中一般不用（）。
A、醋
B、胡椒粉
C、盐
D、芥末
