$("p")

Select all paragraphs

$("p[b]")

Select all paragraphs with bold text

$("p:odd")

Select all odd paragraphs

$("p:even")

Select all even paragraphs

$("#section2")

Selects section 2 header

$("#section2,p[b]")

Selects section 2 header and all odd paragraphs

$("p.important[b]")

Select all important paragraphs with bold text

$("p:eq(2)")

Selects third paragraph

$("p[@align]")

Selects all paragraphs with alignment specified

$("p[@align=center]")

Selects all paragraphs with alignment specified to center