18.He aed string of 1 with filament in the rear of one part towel gourd head of a gravelstone.
他在一部分丝瓜尾部用细线吊了一个小石头。
19.The President led the way out of the courtyard, followed by senior ministers of government. Junior ministers brought up the rear.
总统率先走出庭院,后面跟着政府高级部长,走在最后是级别较低部长。
20.A new dynamic model is developed for simulating the widely tunable grating assisted codirectional coupler with rear sampled grating reflector (GCSR) lasers.