Early chemists had to use indirect means for determining the atomic mass of an element . 早先的化学家只得用间接的方法来确定某种元素的原子质量。
By convention an atom of an element is represented by an abbreviation of the element's name . 按照惯例，一种元素的原子由该元素名称的缩写来表示。
The interval is two mass units because these isotopes of the elements differ by two neutrons . 因为这些元素的同位素相差两个中子，所以其间隔为两个质量单位。
The union of a and b, writeen as aub, is the set of elements which belong to a or b or to both . A与B的并集记为AUB，是属于A或属于B，或同时属于两者的元素的集合。
The combining power of one element in the compound must be equal to the combining power of the other element . 化合物中一种元素的化合价必须等于另一元素的化合价。
we give the wavelengths of the k lines for some of the elements in table 2. 1, in units of cm. 表21中列出某些元素的K线波长，以cm为单位。
But when discussing the assembly of elements we shall express them with reference to a global system . 但是如果我们考虑的是元素的全体，那么我们将在整体编号系统中将它们表示出来。
If the orientations of driving elements are reversed then it is necessary to change a sign in their terminal relations . 如果驱动元素的定向取反了，就必须在它们的端子关系中改变符号。
We are interested in superimposing the effects of all the elements in order to form the system matrices for the whole body . 为了形成整个物体的系统矩阵，我们需要将所有元素的效应叠加起来。
The second-order determinant that multiplies a given element is found by crossing out the row and column in which that element appears . 乘给定元素的二阶行列式是删去该元素出现的行和列而得到的。
