combining expressions in mathplot

Is there a cleaner way of combining two expressions.

This example works and gives what I want

plot(1:10)
aa<- expression(alpha==.05)
bb<- expression(beta ==.80)
aabb<- expression(alpha==.05 ~ ", " ~ beta ==.80)

text(5, 10, aa)
text(5,  9, bb)
text(5,  8, aabb)

text(5,1, parse(text=paste(deparse(aa[[1]]), deparse(bb[[1]]), sep="~")))

text(5,2, parse(text=paste(deparse(aa[[1]]), deparse(bb[[1]]), sep="~',
'~")))

Is there a cleaner way of combining the expressions aa and bb  to get the
effect of the last two lines?

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