پرسش‌ها با دسته‌بندی (زبان انگلیسی => زبان انگلیسی => گرامر)

The more advanced the specialization in production and the more complex the  economy, ……… to make any given good reach its ultimate user by using barter. 

Celluloid and plastics have largely replaced genuine ivory in the manufacture ………  buttons, billiard balls, and piano keys. 

سلام در جمله زیر چرا بعد از فعل ، s به کار رفته ؟ در صورتی که پاسخ میتونه چند نفر باشه Who helps lost children ? 

Celluloid and plastics have largely replaced genuine ivory in the manufacture ....... buttons, billiard balls, and piano keys.

Celluloid and plastics have largely replaced genuine ivory in the manufacture ……… buttons, billiard balls, and piano keys.

تفاوت حال کامل و حال کامل استمراری و همچنین گذشته کامل و گذشته کامل چیست ممنون میشم با مثال توضیح بدین 

 Iron came from west Asia, although its routines of diffusion were somewhat different  ....... agriculture.  

 Mars, the fourth planet from the Sun, ...... of sky gazers. 

فرق دو جمله ی انگلیسی زیر  از لحاظ گرامری و معنی  چیه ؟ i cut my hair last week i got my hair cut last week

 The more advanced the specialization in production and the more complex the  economy, ……… to make any given good reach its ultimate user by using barter.