Singular or plural: "bird's nest" and "apple tree"

> 为啥鸟巢用 bird's nest 而苹果树没有's呢？
> 还有为啥是bird's nest 而不是birds' nest呢？？
> 为啥是apple tree 而不是apples tree呢？

I'm not sure why we don't say birds' (or birds's) nest, even though the nest we're referring to should be for more than one "bird". Just remember it for now.

"Apples tree" is wrong. You always use singular noun as an adjective, like "car mechanic", "computer network" (even though the network connects to many computers).

> 我知道100-meter race这种表达是对的
> 但是有没有 100 meters race这种表达的？！
> 或者是应该100 meters' race?

100-meter race or 100 meters race. Either one is OK. I'm not sure if I've seen 100 meters' race (with an apostrophe). Also see message 8 by yuzhoucn at
http://forum.putclub.com/viewthread.php?tid=145045&extra=page%3D1

How to read keyboard symbols

~	tilde (sounds like til-da); be prepared to explain to non-technical people saying "you know, the wave-shaped thingy"
!	exclamation; commonly read as bang in computer shell programming as in #!/bin/sh
@	at
#	pound; but commonly read as shee in computer shell programming as in #!/bin/sh, not sure why
$	dollar
%	percent
^	caret; not many people know this word so be prepared to say "no, not carrot; it's the character above 6, an arrow pointing up"
&	ampersand
*	star; some read asterisk
(	opening parenthesis (some may shorten it saying paren)
)	closing parenthesis
_	underscore; once I heard people say underbar
+	plus
-	minus, hyphen; as symbol before arguments in commands, some people including me read dash, easier to say one syllable
=	equals
`	backtick or backquote
{	opening brace
}	closing brace
[	opening bracket
]	closing bracket
|	pipe or vertical bar
\	backslash; be prepared to explain to some non-technical people
:	colon
;	semicolon
"	double quote
'	single quote
<	less than; some may read left angle bracket
>	greater than
,	comma
.	dot; period if in English text
?	question mark
/	slash or forward slash; some non-technical people may be confused about / and \
	space
(), [] and {}	may also be called brackets in general. In that case, they specifically call [] square brackets and {} curly brackets. I never like this. Open and closing may also be called left and right.