I.  Behind a noun:

• amount + ほど + positive = about, approximately
この仕事は一週間ほどかかります。This work takes about a week.
 
• noun + ほど + negative = not so much, not as much
この冬は去年ほど寒くない。This winter is not as cold as last year.
てんぷらも高いが、すしほどではない。
Tempura is expensive but not as expensive as sushi.
 
• noun + ほど + adjective-plain + ものはない = nothing is as . . . as. . .
日本語ほどおもしろいものはない。Nothing is as interesting as Japanese.
 

• verb-plain1 + のは + verb-plain2 ほど + negative = not as . . . as. . .
話すのは書くほど難しくない。Talking is not as hard as writing.
 
• verb-plain + ほど = as . . . as . . . , to that extent, to that degree
おかしくて涙が出たほどです。It was so funny my tears came out.
涙が出るほど笑ってしまった。(I) laughed until tears came out.
心配するほどのことはありませんよ。It's not worth worrying.
 
• verb1-ば + verb2 + ほど = the more . . .  the more . . .
聞けば聞くほどおもしろくなってくる。
The more I hear, the more interesting it becomes.
 
 

•  In the "amount + ほど + positive" pattern, ほど may be replaced by ぐらい or ばかり。　Go to gurai (ぐらい)    Go to bakari (ばかり)
この仕事は一週間ほどかかります。 This work takes about a week.
この仕事は一週間ぐらいかかります。 This work takes about a week.
この仕事は一週間 ばかりかかります。 This work takes about a week.