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.
