I don't very often have a full day off work. Today I did. I had a leisurely morning, going to the gym, ____(walk) the dog, feeding my friend's cat, and thought I would hurry into the office at Job number 2, to fill in my time sheet so I would ____ (pay) for the hours I have worked. I was thinking that I had worked less hours because the lady I share job with was working instead ____ me. I prayed then, that somehow we would have ____ (much) money coming in this month and imagined money coming in to my bank account.

    I arrived at the office to see the main secretary looking very pale. She asked what my afternoon ____ (plan) were, when I said I had the afternoon free she asked me ____ I could work for her, as she had really hurt her back. I was really looking forward to a day off, but she looked in such pain that I said yes straight away. She did a quick handover of what____(be) urgent and needed to be done.

    I raced home and got ____(change) into work appropriate clothes and took over. Our boss phoned and thanked me for steeping in so that everything went ____(smooth). Thee unwell person went home, and I got four hours extra pay. It's amazing how ____universe works.

白令海峡是连接美洲和亚欧大陆的交通要道。海峡及东西两侧陆地都位于西十一区。在白令海峡修建海底隧道的设想是一名法国工程师在一个多世纪之前首次提出的。目前俄罗斯计划出巨资修建白令海峡海底隧道，打通俄罗斯至美国阿拉斯加的铁路。下列因素不属于修建隧道两侧铁路的主要自然障碍是（    ）