根据汉语提示，用词组的适当形式填空。

1. Chinese _________ _________ (医疗保健) has already improved.

2. _________ _________ (由于) your help,I passed the English exam.

3. Great changes have _________ _________ (发生) in China.

4. It makes me _________ __________ (感到愉快) to know my work is appreciated.

5. The watermelon is very big. I have to _________ it ________ (把…分成) three parts

     so that we can have one part each.