cho a,b>0 

c/m \(\dfrac{a^3}{a^2+b^2}\)-\(\dfrac{b^3}{b^2+1}\)+\(\dfrac{1}{a^2+1}\)≥\(\dfrac{a+b+1}{2}\)

1. can you really concentrate .. two things at once

a. on b.in c. of d. for

2. this may ba a more than usually ... period of your life

a.stress b. stressed c.stressing d. stressful

some people like studying at night when it is quiet , whereas orthers find the early morning is a ... time to get thing done

a. good b. best  c.worse d.well

because of the increasing enrolment , the school has to employ teachers who are not ... for the job

a. qualifying  b. qualifyed  c. worth  d. skilled

my friend and i were very happy ... the result of the election .

a.on   b. to  c. about  d. for