To keep health, Professor Johnson _____ cycling as a regular form of exercise after he retired. [ ]

A. caught on

B. took up

C. carried out

D. made for

TOSI锅炉末级过热器入口烟温，在控制负荷时为（）℃。在额定连续负荷时为（）℃，在最大连续负荷时为（）℃。