1.Mr Zhao is a good teather,he makes ___easy to learn English.A.it B.this C.that D.us2.Mum asked the boy ___in that river,it's dangerousA.to swim B.tonot swim C.don't swim D.not toswim 3.I'm sorry ,Mr Miller,I'm late ____the traffic is busyA.becauseB.because of C.for D.why4.Tony is good at mathTony ___ ________math(改为同义句）