Questions * ( от предложения I went to school yesterday ) : 1) I went to school yesterday, didn't I ? 2)where did I go yesterday ? 3) when did I go to school ? 4) did I go to school or park yesterday ? 5) who went to school yesterday ?( He swam at the swimming pool two days ago) 6)He swam at the swimming pool two days ago, didn't he ?7) who swam at the swimming pool two days ago ? 8) where did he swim two days ago ? 9) when did he swim at the swimming pool ? 10) did He swim at the swimming pool two or five days ago ?
1) During this period the track structure has been substantially improved. One of the greatest improvements was the elimination of rail joints. In order to reduce the number of joints the rails are welded into continuous lengths.These continuous or long welded rails have greater strength and provide a smoother running of trains at far greater speeds. 2) Another improvement which has made it possible to increase speeds on railways is the use of concrete sleepers. Thus in some countries , concrete sleepers have replaced wooden ones on heavily used main lines because of their advantages. Concrete sleepers have a longer life and a far greater weight than those made of wood. The greater weight of concrete sleepers provides the greater stability of track. It is this factor which has greatly contributed to increased speeds.
ответ взял прямо из текста. Насколько я помню, так надо делать в подобных заданиях.
