在乙型肝炎病毒（HBV）基因组S、C、P和X区4个开放性读码框架（ORE）中，最易发生变异的是（）
Many cast iron pistons are designed with heat dams, which serve to （）
An aluminum piston has lower inertia and higher coefficient of （） compared to that of cast iron.
在高尔夫术语中，“Iron”的意思是（）。
A number of cylinder liners are enclosed in one cast iron casing to form a （）.
Cast iron pistons used in large propulsion diesel engines are constructed with （）
The smith soon（）three iron shoes for the horse.
在乙型肝炎病毒（HBV）基因组S、C、P和X区4个开放性读码框架（ORE）中，最易发生变异的是（）。
At the magnetic equator there is no induced magnetism in the vertical soft iron because（）.
An advantage of aluminum pistons, when compared to cast iron pistons is （）.
The children went there to watch the iron tower ______ .
e. Vitamin C supplements may be combined with iron supplements to increase iron absorption.
which substance in body contains iron?
Iron is more useful ______ any other metal.
听力原文：Watches, which ore really small clocks, were first made during the sixteenth century. The earliest watches were made of heavy iron, and people wore them hanging from their belts. Little by little, watches were made smaller so that they could be carried more easily. The invention of the machinery for the mass production of these parts of clocks and watches was an important step in making clocks and watches available to the general public. In some watches, small pieces of precious stones, such as rubies or sapphires, are used at the points on which the wheels mm. Since these stones are very hard, they do not wear down very easily under the friction of the moving wheels. Thus a watch utilizing such stones will keep accurate time over a much longer period than other watches.
（)The settlers introduced iron tools, muskets for hunting, domesticated animals, and
Strike the iron while it is hot. _____________ （四字格)。
When carbon is added to iron in proper__, the result is steel（）
weallthinkthatmary’shusandisavery（oring）person（）
“铁影壁”是元代的文物。译：The Iron Screen is（)of the Yuan Dynasty.
