HCN是直线型分子,所以它是非极性分子。
参考答案:错
—I find it very difficult to read _________novel you lent me last week.
—Yes. It’s necessary to have __________good knowledge of history.
A.the;不填
B.a;不填
C.the;a
D.a;a
小明、小亮、小丽、小刚站成一排照相,小丽要站在第二个(从左往右数),一共有多少种排法?请一一列举出来.