Since September 27, 2004, the jinmeiyō kanji (人名用漢字, kanji for use in personal names) consist of 3,119 characters, containing the jōyō kanji plus an additional 983 kanji found in people's names.
人名用漢字（じんめいよう・かんじ）literally means "person's-name-use kanji" or "kanji for use in peoples' names."
Kanji have been added and (re)moved from the list several times throughout its history. See the page Wikipedia: Jinmeiyoo Kanji
The jōyō kanji (常用漢字, regular-use kanji) are 2,136 characters consisting of all the Kyōiku kanji, plus 1,130 additional kanji taught in junior high and high school[9].
常用（じょうよう）漢字（かんじ）means "daily use" kanji.
The grade-level breakdown of these kanji is known as the gakunen-betsu kanji haitōhyō (学年別漢字配当表), or the gakushū kanji. (ja:学年別漢字配当表)
Also known as Kyōiku kanji (教育漢字, literally "education kanji"). see Wikipedia: Kyouiku Kanji
Some characters were given simplified glyphs, called shinjitai (新字体). Many variant forms of characters and obscure alternatives for common characters were officially discouraged.
The simplification of Japanese kanji was done to a lesser extent than that of the Chinese hanzi.
Becauseでしょう indicates guess, it can be used for current events and past events that we are not certain.
This is like the subjunctive in English and Spanish, but instead uses a form or the copula, です, instead of conjugating the verb into another form.
I think textbook writers and publishers have the responsibility to tell learners that ています has more than one function.
In any kind of textbook, if there is an aspect to a concept which will cause confusion in the future, it should be covered, even if only in a footnote, so that the reader can study it on their own.
ています can be used to mean an action (instantaneous or continuative) takes place on a regular basis.
For example, "Every year, many people die," or "Every day, he goes to work."
For English, telling the difference between instantaneous and continuative verbs is easy, because we seldom, if ever, use “be +ing” form for the former. For Japanese, however, the situation is complicated, as ていますcan be used with both kinds of verb.
There is no way to tell the continuity of a verb by simply looking at it. One must understand the concept before knowing the full meaning when paired with ています.
use ‘本を貸していただけませんでしょうか’ to make it even politer.
book PRT-OBJ lend/give-TE_FORM it-is-acceptable-NEG COPULA-SUGGESTIVE PRT-INTERROGATIVE. "Is it not acceptable to give me your book?"
‘本を貸してくださいませんか’ (Can’t you lend me your book?)
(your) book PRT-OBJ give-TE_FRM please-NEG (cannot) PRT-INTEROG (?). "Can't you give/lend me your book?"
Using くださいません is the negative of ください which, when coupled with か makes a polite order in the form of a question: instead of "Please give me your book," it is "Can't you lend me your book?"
By asking questions, the listeners feel that they have a choice to say no and thus are not offended by your request. In Japanese, you should also ask questions when you ask for a favor.
When you ask a question, you give the other person(s) the choice to say "Yes" or "No." This is much more polite than any order using 下さい.
when you ask the same people to do something FOR you, e.g. lend you a book or sign a recommendation letter for you, you can’t just use ください.
This is like a homeless person saying "give me money, sir." It is still an order.