You can only be sure of _______ you have at present; you cannot be sure of something _______ you might get in the future.

mber of the students in senior high school, ____ is mentioned above, is increasing.

All the students agreed to go to Qingdao by _______ sea and camp by _______ sea.

The medical team left the village with great satisfaction,________a lot of local villagers. [ ]

No one knows exactly when the first peoplearrived in _______ is now called California.