二氧化碳分析仪使用时分析气流量保持在()L/min左右。
A、0.5
B、1.0
C、1.5
D、2.0
参考答案:A
—_____ in the lake?
—There's a beautiful boat.[ ]
A. What
B. What's
C. How many
D. Where
Protect yourself from strong sunlight. You know, skin cancer can be caused by too much ________ the
sun. [ ]
A. contact with
B. experiment on
C. exposure to
D. exhibition of