Look at the following train timetable. According to the information in the timetable and complete the sentences with the right words.　(每空一词)

小题1:The first train to London on a Saturday leaves Leeds at _______ to seven.

小题2:The nine ten train runs only on _______.

小题3:The trains at 6:45 and _______ arrive in London before ten o'clock.

小题4:There are _______ trains to London every Monday morning.

小题5:The ten thirty train on a Saturday is the _______ one.

石膏类模型材料的凝固原理是（）

A.CaSO₄·1/2H₂O→CaSO₄·H₂O

B.CaSO₄·1/2H₂O→CaSO₄·2H₂O

C.CaSO₄·H₂O→CaSO₄4·2H₂O

D.CaSO₄·2H₂O→CaSO₄·H₂O

E.CaSO₄·2H₂O→CaSO₄·1/2H₂O