英语长句分析
Official recognition that foreign technology could play a major role in modernising the Chinese economy had caused imports to rise by more than 50 per cent in 1978 placing undue strain on the national economy.该句中 placing undue strain on the national economy 是什么成分?这个句子本身有没什么问题?本人菜鸟
placing undue strain on the national economy 是什么成分？为什么用现在分词？