The old buildings, _____ the seventeenth century, were destroyed in the earthquake.

----What’s it that cost him the job?----_______ experience .He was always very nervous.

 Oil prices have risen by 32 percent since the start of the year，________ a record US $57.65 a barrel on April 4.

---She’s feeling very sad over___ of school trip tomorrow. ---So would you if you fell ill on such an occasion.

(2013·凉山一模)Life is like riding a bicycle. ________ your balance, you must keep moving.