Here:

sync on : sync rate 30 : hide mouse : dim line1(3) : dim line2(3) : dim line3(3) : dim line4(3) : line2(3)=100 : line3(3)=200 : line4(3)=300 : ballx=320 : bally=440
do
score=score+1 : set cursor 0,0 : print "Score: ",score
if line1(3)<=0 then line1(1)=rnd(440)+100 : line1(2)=line1(1)+75 : line1(3)=480
if line2(3)<=0 then line2(1)=rnd(440)+100 : line2(2)=line2(1)+75 : line2(3)=480
if line3(3)<=0 then line3(1)=rnd(440)+100 : line3(2)=line3(1)+75 : line3(3)=480
if line4(3)<=0 then line4(1)=rnd(440)+100 : line4(2)=line4(1)+75 : line4(3)=480
line1(3)=line1(3)-5 : line2(3)=line2(3)-5 : line3(3)=line3(3)-5 : line4(3)=line4(3)-5
line 0,line1(3),line1(1),line1(3) : line line1(2),line1(3),640,line1(3) : line 0,line2(3),line2(1),line2(3) : line line2(2),line2(3),640,line2(3)
line 0,line3(3),line3(1),line3(3) : line line3(2),line3(3),640,line3(3) : line 0,line4(3),line4(1),line4(3) : line line4(2),line4(3),640,line4(3)
if bally=>line1(3)-10 and bally=<line1(3) then if ballx-10<line1(1) or ballx+10>line1(1)+50 then bally=bally-10
if bally=>line2(3)-10 and bally=<line2(3) then if ballx-10<line2(1) or ballx+10>line2(1)+50 then bally=bally-10
if bally=>line3(3)-10 and bally=<line3(3) then if ballx-10<line3(1) or ballx+10>line3(1)+50 then bally=bally-10
if bally=>line4(3)-10 and bally=<line4(3) then if ballx-10<line4(1) or ballx+10>line4(1)+50 then bally=bally-10
if leftkey()=1 and ballx>20 then ballx=ballx-10
if rightkey()=1 and ballx<620 then ballx=ballx+10
if bally>470 then bally=470
bally=bally+5 : circle ballx,bally-10,20
if bally=<10 then exit prompt "Score: "+str$(score),"Game Over!" : end
sync : cls : loop