The twins are so much alike that it is difficult to tell one from________.

-Does it often rain in Jinan? -No,         was little rain in Jinan last winter.

All of us find ________ necessary to take exercise every day. 

If you don’t know how to use the word, you should _________ in a dictionary.

— How pleasant 　　　 is to go fishing with my father! — Yes. Parents and children should spend more time together.