Vitamin D helps our bodies make a special chemical, and this special chemical, _______, affects our brains, making us feel happy.
35..It's the second time you_________late this week. 36.
37.It will not be__________we meet again. 38.
39.It's demanded that we____________there on foot. 40.
41.“It” is often used to________a baby. 42.
43.It was not until 1936________basketball became a regular part of the Olympic Games. 44.