内容正文:
Stainless steel lab ware. Never use hydrochloric acid on steel products. A soft and clean cloth can be
used. There are also stainless steel pads that can be used. 5. E Usually these steel products have visible
polishing grains or lines that must be followed as directions for cleaning. Filtered water is the recommended
liquid for cleaning. Some unfiltered water can contain deposit built up that can protect the equipment.
A. Note that each chemical is unique.
B. Note that the cleaner doesnt have strong PH.
C. There are instances in which water is used for the last cleaning.
D. It is still best that you check cleaning instructions in the packaging.
E. Howeverꎬthe manner of cleaning or polishing must be correctly observed.
F. This type of equipment is usually used as a holder for chemicals to be tested.
G. You use different science equipment to help you produce conclusions on given problems.
Ⅲ. 语法填空
阅读下面短文ꎬ在空白处填入 1 个适当的单词或括号内单词的正确形式ꎮ
Astronomy is the oldest science 1. known (know) to man. Thousands of years ago man looked at the
stars and wondered about the heavens. But man was 2. limited ( limit) by the six planets that he could
see only 3. with his eyes alone. The Greeks studied astronomy over 2ꎬ000 years ago. They could see the
size colourꎬand 4. brightness ( bright) of a star. They could see its place in the sky. They watched the
stars 5. move (move )as the seasons changed. But the Greeks had no tools to help themselves study the
heavens. Each new tool added to the field of astronomy helped man reach out into space. Man knew a little
about the moon 6. until there were telescopes.
He did not know that the planet called Saturn had 7. rings ( ring) around it. His sight was
8. so limited that he could not see all the planets. In the early 1700sꎬpeople thought there were only six
planets. Before the spectroscopeꎬman did not know wha