In such cases
In support of this claim
In support of what I have been saying
In the first place
In the first place, then, I say
In the first place there is
In the last resort
In the light of these things
In this connection
In this point of view, doubtless
In this situation, let us
In this respect they are
In view of these facts, I say
In what I have to say
Is it fair to say that
Is it not evident that
Is it not quite possible that
Is it said that
Is not that the common sentiment? 
Is there any reason for
It affords me unusual pleasure
It is but too true that
It can scarcely be imagined that
It can not be too often repeated
It certainly follows, then,
It does not appear to me
It has been maintained that
It has been more than hinted that
It has been said, and said truly,
It has sometimes been remarked that
It is a common observation that
It is a curious fact that
It is a fact patent to any one that
It is a melancholy fact that
It is a notorious fact that
It is a thing commonly said that
It is a very serious matter. 
It is a very serious question
It is also to be borne in mind
It is amazing that there are any among us
It is an additional satisfaction
It is an undeniable truth that
It is apparent that
It is certain that
It is certainly not sufficient to say
It is difficult to conceive that
It is exceedingly unlikely that
It is historically certain that
It is in effect the reply of
It is in quite another kind, however,
It is, indeed, commonly said
It is more difficult to
It is necessary to account for
It is no more than fitting that
It is not a good thing to see
It is not a wise thing to
It is not alleged
It is not chiefly, however,
It is not for me here to recall
It is not, however,
It is not long since I had occasion
It is not my purpose to discuss
It is not necessary that I define
It is not proposed to
It is not surprizing that
It is not to be denied that
It is not told traditionally
It is not true that
It is not wonderful that
It is observable enough
It is of little consequence
It is of importance that
It is of very little importance what
It is quite true that
It is related of
It is singular that
It is the most extraordinary thing that
It is to my mind a
It is true, indeed, that
It is well known that
It is well that we clearly apprehend
It is wholly unnecessary
It is worthy of remark
It looks to me to be
It may be a matter of doubt
It may be shown that
It may be suggested that
It may be supposed that
It may in a measure be true that
It may not be improper for me to suggest
It must be borne in mind that
It must be confest that
It must be recollected that
It need hardly be said that