They became friends again that day. Until then, they _____ to each other for nearly two years.

Principal White has been working in the school for about 20 years,      all his energy to teaching and researching as well as the running of a healthy school．

His experiences as a volunteer in the quake-hit areas have changed his attitude toward society and _______ influence his future life．

(2013·福建南平二检)—Does he work hard at his lessons?—Yes, he ________ no effort, as far as I know.

--- What are you busy with? --- The conference        in our city next week.