21．He is always thinking of he can do more for others．
A．what B．how C．whatever D．if
22．Sorry we are late．We the wrong turning．
A．took B．had taken C．were taking D．are taking
23．—Thank you ever so much for your timely help．
— .
A．Glad to hear that B．With pleasure
C．Think nothing of it D．All right
24．Please believe me do my homework by myself yesterday．
A．do B．have to C．did D．actually
