AnA4sizedpanel(太阳能板)putontothebackofajacketcosts__________US$15.Itcould__________acellphoneduringasummerwalk.
Atthismomentthebellrang,________theendofclass.
— How are you today? —Oh, I __________ as ill as I do now for a long time.
You look not a bit older than you did 5 years ago. How do you __________so young?