Paul works in a power plant.It ___ two months since he ___ a

Paul works in a power plant.It ___ two months since he ___ a Paul works in a power plant.It____two months since he___a co There are ___ months in a year I ___(know) him since he ___(is)a child 填空：this is ___studies hard my father is a ___.he works in a Mr.White works as a journalist at present,but he ___ in a hi this is a ___(sand )field ,so you can't plant any rice in it My brother ___ works in that factory,he has become a bus dri The old professor still works hard though he is ___ A.in his by June next month,he ___(be) in hospital for two months for It ___ five years since he left for Beijing.A.was B.had been He works a plower plant.为什么works要加s?