.Most of his savings ______ in the Xin Hua Bank

It’s best to stay indoors, ________when PM2.5 has reached dangerous levels.

Everyone needs friends. How can we find a friend and _____ well with each other .-Maybe I can give you some advice .

The fact has worried many scientists _____ the earth is becoming warmer and warmer these years. [ ]

It seems that living green is easy and affordable A small step makes a big difference