原式=:2√3-2√2+(√2-1）/（√2+1)(√2-1)-2(√3-1)/(√3+1)(√3-1)
=:2√3-2√2+(√2-1)/(2-1)-2(√3-1)/(3-1)
=2√3-2√2+√2-1-2√3+2
=-√2+1