In the past few years, research has suggested that Vitamin D may increase the level of serotonin(血清素), one of the key nurotransmitters influencing our mood, and ________it helps to relieve mood disorders.
----Just my luck! The computer broke down again. ----There are so many _____.You can try another one.
---Then see you on New Year’s Day. --- So long! And_____!
If this plan works, we'll ______ in a special way,say, holding a tea get-together.
Could you find me some materials______to human rights on which I’m writing an articles?
The old couple’s son really_____with the other students in the new class, as they expected.