A strength-based approach to performance management requires an appreciative climate in which managers:

An appreciated gift and the gesture of providing it will ______ your coworker's day.

A: look up

B; light up

C; lift to

Most sources of illumination generate light over an appreciable period, and indeed if

an object is lit for a very brief time(less that 1/25 second), the human eye will not react

in time to see the object. A photographic emulsion---that is, a light-sensitive coating on

photographic film, paper, or glass--will, however, record much shorter bursts of light. A

(5) photographic flash can therefore be used to capture high-speed movement on film as well

as to correct deficiencies of the normal surrounding lighting. Photoflash is now generated

electronically, but the earliest form, first used in 1864, was a paper bag containing

magnesium wire and some oxygen-rich substance, such as potassium chlorate. When the

bag was ignited, the metal burned with an intense flash. A contemporary observer reported

(10) that "this quite unsafe device seems to have done nothing worse that engulf the room in

dense smoke and lead to pictures of dubious quality and odd poses."

The evolution of the photoflash was slow, flashbulbs, containing fine wire made of a

metal, such as magnesium or aluminum, capable of being ignited in an atmosphere of pure oxygen

at low pressure, were introduced only in the 1920's.In the earliest type, the metal

(15) was separated from the oxygen by a thin glass bulb. The dash was fired by piercing the

bulb and allowing the oxygen to come into contact with the metal, which ignited

spontaneously. Later bulbs were fired by an electric battery, which heated the wire by

passing a small current through it. Other combinations, such as the pairing of oxygen

difluoride with zirconium, have also been used. In each case enough energy is given out to

(20) heat the oxidizable metal momentarily to a white-hot emission of visible light. The smoke

particles are so small that they cool rapidly; but since they are white, they contribute to the

brilliance by reflecting the light from their still-glowing neighbors. A slightly bigger form

of the metal will burn for a longer time.

What does the passage mainly discuss?

A．The history of the photoflash

B．Theories about how the eye reacts to light

C．The technology of modern photography

D．The dangers of using the early photoflash

We appreciate your suggestion () establish agency relationship between our banks .

A. to

B. that

C. we

D. for

Nowadays teenagers are not______to stand and appreciate works of art; they prefer to participate in them.

A．content

B．controversial

C．confident

D．conspicuous