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皮皮学刷刷变学霸
举一反三
【单选题】I'm sorry you've waited so long, but there will be some time _______ Bran gets back
A.
when
B.
since
C.
till
D.
after
【简答题】What should you do if a machine jams
【单选题】—I've not finished with my dinner yet. —But our friends______for us.
A.
waited
B.
to be waited
C.
waiting
D.
are waiting
【单选题】---Did you wait for him long? ---No, I hadn’t waited long _______ he appeared.
A.
unless
B.
until
C.
before
D.
since
【简答题】lf a machine jams, take time to undo the jam or to tell the proper person to attend to it.
【单选题】Bobby: Where's the food I ordered? I've waited for thirty minutes! Waiter: I'm really sorry, but the kitchen is very busy. You'll have it _______. [ ]
A.
already
B.
early
C.
once
D.
soon
【单选题】One of the great revolutions of all time that occurred in 1948 was ______.
A.
the invention of a transistor
B.
the discovery of silicon
C.
the production of a crystal called a diode working like a valve
D.
the beginning of the start of microelectronics
【多选题】(), () and( ) are electronic components.
A.
vacuum tube
B.
integrated circuit
C.
silicon
D.
transistor
【单选题】Which electronic component is this graphical symbol illustrating?
A.
Diode
B.
Tunnel diode.
C.
Transistor
D.
Silicon controlled rectifier.
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