A. 出口商品交易会上，一家合资企业正在酝酿之中。 B. 出口商品交易会上，一家合资企业正在工作着。 C. 一家合资企业正在出口商品交易会上进行交易。 D. 一家合资企业在出口商品交易会上准备成立。
单项选择题We（）that you'd be able to visit us, but you didn' t.
A. had hoped B. would hope C. are hoping D. hope
单项选择题The population of cities in the Eastern and Northern areas of the United States is declining while（）southern cities is growing.
A. that in B. that of C. those of D. those in
