. _______ on time, this medicine will be quite effective.
286. In 1920 Poland and Russia were still at _______and they mustn’t trade in agricultural products with each other.
285. In the hotel semi-skilled workers include chambermaids (客房女服务员) and______ or waitress, who must have training for their particular duties.
284. The officers led their men to _______ in battle, so all the villagers came out to award them with food and drink on both sides of the road.
283. The house was sold for 60,000 dollars, which was far more than its real _______ .
282. Our earth, one planet of the solar system, is only a very small part of the__________.