用白铁皮做罐头盒,每张铁皮可制盒身l0个或制盒底40个,一个盒身与两个盒底配成一套罐头盒,现有l20张白铁皮,设用张制盒身,张制盒底,得方程组( )
I_______ books in the library when the rainstorm came.( )
read
reads
am reading
was reading
﹣﹣﹣_________ your hands before dinner,Tony.
﹣﹣﹣No problem,Mom.( )
Wash
Washes
Washing
To wash
﹣﹣﹣Is Helen here?
﹣﹣﹣No,she isn't here.She_______ in half an hour.( )
arrives
arrived
will arrive
has arrived
This Saturday is my_______ birthday.( )
fourteen
fourteenth
forty
the fortieth
The price of this piano is a little ________ .I can't afford it.( )
cheap
expensive
low
high