______ do teenagers need to sleep ？
At least eight hours a night．（ ）
| A． |
How long |
B． |
How many |
C． |
How often |
In Switzerland，things like glass and plastic into different groups and then recycled（ ）
A．separateB．separated
C．are separatedD．is separated
Watch out，Peter! is a little boy playing ahead on the road．（ ）
A．ItB．ThisC．ThatD．There
My grandma's hobby is cooking watching TV，It's square dancing （ ）
A．not only；but alsoB．neither；nor
C．both；andD．either；or
It seems that El Nino some disasters in the world in the past few months （ ）
A．has causedB．is causingC．will causeD．caused
do you go to Mrs Rainbow's colour therapy？
Once every two weeks．（ ）
A．How oftenB．How soonC．How longD．How far