Incidentally, be it noted, that beside human beings, monkeys are the only creatures with whom the sexual impulse is not limited to certain periods.
That natural impulses are implanted in women as well as in men and that these manifest themselves particularly strongly at certain periods of a woman's life, does not alter their judgment.
It requires good and sufficient nourishment and atcertain periods it requires rest.
At certain periodsof the year, when all hands are required, such as harvest, etc.
But though there was great variety in their countenances, there was not much beauty; and besides, dinner was by this time ready, which has at certain periods a charm even greater than art.
Their flesh is held in slight estimation, and at certain periods of the year is even said to be dangerous.
Rooted in the soil and upon rocks, the form of its branches many times subdivided, above all, the coloured appendages which at certain periods so closely resemble the corolla of a flower, have all the form and appearance of plants.
A part of the circumference of the wheel g, has teeth which are intended at certain periods of its revolution to take into a toothed pinion, fixed upon the top of a vertical shaft h h.
From the upper part of each forked frame, a perpendicular pin extends, which pins when inserted into the sockets l l l, in front of the chain, form axles for the frames to turn upon at certain periods of the operation.
These are very similar to the occasional discharge of a thin fluid from the nostrils of some people, which recurs at certain periods, and differs from defective absorption.
These nervous pains (as they are called) frequently return at certain periods of time, and are also frequently succeeded by convulsions; in these cases if opium removes the pain, the convulsions do not come on.
In passing be it observed that the fact that, besides man, monkeys are the only beings with whom the sexual impulse is not fixed to certain periods, is a striking proof of the relationship between the two.
The above list will hopefully provide you with a few useful examples demonstrating the appropriate usage of "certain periods" in a variety of sentences. We hope that you will now be able to make sentences using this group of words.