Now, I am starting to use vim to edit normal text, that is, other than programming code. Thus, a line is really a paragraph, and is usually long. In the very end of the current GUI window, there are some more space, but if it is shorter than the next line, that is not shown and space is wasted. This effectively makes my window (already being split) quite small. In such case, how to make vim to split the next line, partly shown in the current window, leaving the rest displayed in next window, so that I see the latter half when I press ctrl-F? Shown is a part of an essay I wrote in Chinese, with screenshot cropped at the lower half of the GUI window. As you can see, there is plenty of space between line 14 and the display of current filename, but line 15 is too long to be fit in such space. I bet someone has asked this, but I don't know the name of this action, nor the keyword to find this information. 
To split long paragraph to next window
vim windows;navigation
I found myself that it is :set display=lastline (where @@@ at the end of the last line indicates that line is unfinished), or :set display=truncate (where @@@, starting on a new line, displayed as the last line, indicates the same). To quote :help 'display':'display' 'dy'      string   (default , set to truncate in                            |defaults.vim|)         global         {not in Vi}   Change the way text is displayed.  This is comma separated list of   flags:   lastline   When included, as much as possible of the last line         in a window will be displayed.  @@@ is put in the         last columns of the last screen line to indicate the         rest of the line is not displayed.   truncate   Like lastline, but @@@ is displayed in the first         column of the last screen line.  Overrules lastline.   uhex      Show unprintable characters hexadecimal as <xx>         instead of using ^C and ~C.   When neither lastline nor truncate is included, a last line that   doesn't fit is replaced with @ lines.And I add this line shown and wrote a function, in order to toggle, using ctrl-d, between display=truncate (when I am writing prose and dealing with long lines) display= (when I am writing anything consisting of short lines, such as code). In .vimrc: Display, as much as possible, the next line not able to be fully shownset display=noremap <leader>d :call DisplayLastLine()<CR>function! DisplayLastLine()    if &display == ''        let &display = 'truncate'    else        let &display = ''    endifendfunction(Quicker than all of you this time, maybe because Americans are sleeping.)