As we all know, using public chopsticks ________ necessary when we eat with others.
A.is B.are C.was
After-school activities help students gain more skills and teach ________ to care about others.
A.me B.you C.them
— Krystal, do you know how tea is produced?
— Yes. When tea leaves are ready, they are picked by hand and then ________ for processing.
A.send B.are sent C.were sent
In difficult times, there are always national heroes ________ step up and bring people hope.
A.whom B.which C.who
Even if we learn something well, we will forget it ________ we use it.
A.while B.until C.unless
With the improvement in transportation, students in some small villages no longer go on ropeways ______ rivers to schools.
A.to cross B.crossing C.crossed
