What is the difference between open-die and closed-die forging?lllustrate.Give an example of a metal product produced by each process.

- Who closed the door? -Nobody. It( ) A: was closed by itself B: had closed itself C: was closed itself D: closed itself

It was common practice then that when the store owners wantedto go on vacation theysimply . A: closed in B: closed on C: closed down D: closed up

That’s why we have to catch one before they ______. A: die of B: die from C: die out D: die away

If too many of these rare animals are killed, their kind will _______. A: die away B: die down C: die out D: die from

You must keep your eyes （）. A: closed B: close C: be closed D: to closed

The noise of desks___could be heard out in the street. A: opened and closed B: to be opened and closed C: being opened and closed D: having been open and closed

The noise of the desks _____ could be heard in the next classroom. A: being opened and closed B: opened and closed C: having been opened and closed D: to be opened and closed

下列复数形式错误的是_____ A: die Schweinebraten B: die Würster C: die Mensen D: die Plätze

The direction of the jet of coolant lubricant is __________. A: fixed and can be closed B: fixed and can’t be closed C: adjustable and can be closed D: adjustable and can’t be closed