if与select case互换

<%
if time >=#6:00:00# and time<=#11:29:00# then
response.write "<span class='lele'> 早上好！今天又是新的开始！加油啊！</span>"
elseif time >=#11:30:00# and time<=#14:30:00# then
response.write "<span class='lele'>中午好！吃饱饭会更有精神哟！</span>"
elseif time >=#14:31:00# and time<=#17:59:00# then
response.write "<span class='lele'>下午好！今天收益还不错吧！努力哟！</span>"
elseif time >=#18:00:00# and time<=#22:00:00# then
response.write "<span class='lele'>晚上好！是时候放松下心情了哟！</span>"
else
response.write "<span class='lele'>夜深了！早点休息注意身体别太晚哟！</span>"
end if
%>
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<%
dim a
a=time()
select case a
case a >=#6:00:00# and time<=#11:29:00#
response.write "早上好！今天又是新的开始！加油啊"
case a >=#11:30:00# and time<=#14:30:00#
response.write "中午好！吃饱饭会更有精神哟！"
case a >=#14:31:00# and time<=#17:59:00#
response.write "下午好！今天收益还不错吧！努力哟！"
case a >=#18:00:00# and time<=#22:00:00#
response.write "晚上好！是时候放松下心情了哟！"
case else
response.write "夜深了！早点休息注意身体别太晚哟！"
end select
%>

我想问下，怎么if的换成select case的不可以的呢？初学者请问下哪里有错呢？