语法填空
① This included digging up the road, ___________(lay) the track and then building a strong roof over the top.
② But unlike her school friends, 16-year-old Sarah is not spending half-term ____________ (rest).
③ My ambassadorial duties will include ___________(introduce) British visitors to the 120-plus pandas at Chengdu and others at a research centre in the misty mountains of Bifengxia.
④ Leaving the less important things until tomorrow ___________(be) often acceptable.
⑤ Keep ___________(hold) your position for a while.