【单选题】Years ago, many of the machines were operated ______ but now they are operated by computers.
【单选题】In the deserted factory several huge machines were left to rust and decay.
【判断题】三维非稳态温度场可以用t=f(x,y,τ)。
【单选题】It was in this factory ______ 'West Lake' sewing machines were made.
【单选题】All the machines ______ by the end of the following week.
D.
will have been repaired
【单选题】The keys of Sholes' first typing machines were likely to be twisted together.
【单选题】A number of new machines were introduced from abroad,______ an increase in production.
【单选题】The earliest bicycles were called 'running machines' because ______.
A.
people have to run on feet when using the machines
B.
they were faster than running men
C.
the riders could run on the bicycles
D.
the bicycles could run fast automatically
【单选题】______ of the machines on display were made in China.
【判断题】象征性交货的特点是卖方凭单交货,买方凭单付款