It is rude to speak with your mouth full.
口をいっぱいにして話すのは行儀が悪い
It is sad that ....
…は残念だ
It is sheer madness to drive so fast.
そんなにスピードを出すのはまったく愚かなことだ
It is significant that ...
…ということは重要だ
It is silly of you [You are silly] to accept his invitation.
彼の招待を受けるなんていかれてるぞ
It is six of one and half a dozen of the other.
両者とも大差ない，五十歩百歩である
It is [seems] so.
そのとおり［そうらしい］
It is such fun.
たいへん楽しい
It is supposed that his death was an accident.
彼は事故死だと思われている
It is sure to rain.
きっと雨が降る
it is tempting to do
つい…したくなる
It is the last straw that breaks the camel's back.
((諺))ラクダの背骨を砕くのは最後の一本のわらだ
It is the least I can do for him.
それが彼にしてやれるせめてものことだ
It is the only sure method of success.
それがうまくいく唯一確実な方法だ
It is this aspect that I am going to tell you about.
あなたに言いたいのはこの側面に関してだ
It is three hours' drive [a three-hour drive] from here to the town.
町まで車で３時間だ
It is tiresome of him to come incognito.
名前を隠してやってくるとは彼もいやなやつだ
It is too dark to read.
暗くて本が読めない
It is too risky to talk about this issue.
これを話題にするのは危険すぎる
it is too soon to tell if ...
…かどうか言うのは早すぎる
It is traditional for us to do
…するのが我々の伝統だ
It is true that time is money.
時は金なりというのは本当だ
It is true, surely, that ....
…が事実なのは間違いない
It is truly said that ....
…と言うのももっともだ
It is two o'clock.
今２時です
It is typical of him to choose this pub.
このパブを選ぶとは彼らしい
It is unclear whether ....
…かどうか不確かだ
It is understood that ....
…だと聞いて［決まって］いる
It is unfortunate (that) ....
残念なことに…である
It is unlike him to be late for an appointment.
約束に遅れるなんて彼らしくない
It is unnecessary for him to be here.
彼がここにいる必要はない
It is unusual for him to be late.
彼が遅れることは珍しい
It is useless trying [to try] to reason with them.
彼らを説得しようとしてもむだだ
It is usual for him to be late.
彼が遅刻するのはふつうのことだ
It is very dangerous to smoke in bed.
寝タバコは危険だ
It is very generous of you to do ....
…して下さるとはお礼の言葉もありません
It is very irresponsible of him not to answer my letter.
ぼくの手紙に返事をくれないとは彼はまったくいいかげんだ
It is very odd that he should do that.
彼があんなことをするとは奇妙だ（◆It is very odd that he does that.と異なり，話し...
It is vital that ....
…は必須だ
It is whispered that they are deeply in debt.
彼らには大きな借金があるといううわさだ
It is widely believed that ....
…だと一般に考えられている
It is widely [generally, commonly] held that ...
…と一般的に考えられている
It is wisdom to know others.
人を見極めようとするのは賢明だ
It is wise policy to show your face at meetings.
会合には顔を見せるのが得策である
It is wise to accept the offer.
申し出に応じるのは賢明だ
It is within his discretion to hire new personnel.
新社員を雇うのは彼の裁量に任されている
It is wonderful to see you again.
再会できてとてもうれしい
It is worthwhile to have a meeting.
会議をする価値がある
It is wrong of you to insult others.
人を侮辱するのはいけない
It is you who are [is] angry.
腹を立てているのは君のほうだ（◆areのほうが一般的）
