单项选择题

Lens designers today______.

A．have a large source of help to fall back on
B．receive a low salary
C．are less respectable than those of the past
D．are not decisive in the lens design

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热门试题

单项选择题

Which of the following words cannot be used to describe today's lenses

A．More delicate.
B．Numerous.
C．Cheaper.
D．Unpopular.

单项选择题

After the passage the author will talk about______.

A．the principles of designing lenses
B．techniques of making contact lenses
C．the design of photographic lenses
D．styles of lenses