【B4】______A．hatchB．patentC．duplicateD．train

Decreasing returns to scale may arise from ______.A．specialization of inputs.B．duplication

The train from Shanghai is pulling ______.A．inB．outC．offD．back

— I usually go there by train.— _________________A、You could do more training.B、The boat

— What time does the train leave？— _________________.A: On TuesdayB; At half past fiveC;

_________(63)A.establish B.makeC.build D.train

_________(59)A.exercise B.training C.strength D.m