_____ is the first element on the periodic table, making it the lightest element. Since it is so light, it rises in the atmosphere and is therefore rarely found in its pure form.

It is known that hydrogen _____ (be) the lightest element.

The word stress of a compound usually falls on the first element.

Most compounds bear primary stress on the first element.

For semantic unity, the meaning of an idiom is not often ___________in the meaning of each element.

Compound proper nouns normally have a primary stress on the first element.

智慧职教: ______ cannot be hardened by heat treatment since they contain no hardening element.

A DC servo-motor is a type of ( ) applied to automatic control systems A: actuator B: amplifying element C: correcting element D: measuring element

If A is a matrix, the function max(A(:)) is ( ). A: to return the first element B: to return the maximum element in each row of the matrix C: to return the maximum element in each column of the matrix D: to return the largest element of the entire matrix

In the word “greenhouse” has a compound accent, that is, the main stress is on the _____ element. A: first B: second