Thousands of Shiite Muslims rallied Friday, in the southern city of Basra, to show support for Iraq's new constitution and the Shiite-dominated government.
Many of these muslims are rallying before the weekend
This is correct. They are rallying on a friday, which is before the weekend
( z1 rally :ARG0 ( z2 person :mod ( z3 religious-group :name ( z4 name :op "Islam" ) ) :quant ( z5 many ) :mod ( z6 this ) ) :time ( z7 before :op ( z8 weekend ) ) )