填入下面一段文字横线处的语句，最恰当的一句是 （ ） 辣，我们都不陌生，很多人无辣不欢甚至吃辣上瘾，这是因为辣椒素等辣味物质刺激舌头、口腔的神经末梢时，会在大脑中形成类似灼烧的感觉，机体就反射性地出现心跳加速、唾液及汗液分泌增多等现象， ，内啡肽又促进多巴胺的分泌，多巴胺能在短时间内令人高度兴奋，带来“辣椒素快感”，慢慢地我们吃辣就上瘾了。

It takes me a lot of time _________ there by bike.

ientists predict that if presenttrends____, women in 400 years will be 2cm shorter and have healthier hearts

____the old couple as his own parents , the young man did all he could to make sure they lived a happy life .[ ]

－It’s important for us to know _________ all the subjects.－Yeah, group work is my favorite.