This blue bike is too expensive. Could you show me a ______ one?

I know this plan is far from perfect, but I just can’t think of _______one.

—What do you think of Harbin and Qingdao in winter? —I think Harbin is______than Qingdao.

—Which month has ______ days in a year?  —February.

—Which is______，the sun，the moon or the earth?—Of course，the moon is.