Hehasfourson,____(他们全部都是那个偏僻山村里的高级教师)。

Thank you for your help,_____ we could not have finished the work in time.

Hebuiltatelescope____hecouldstudytheskiesinhisfreetime.

Last night he saw two dark _____ enter the building, and then there was the explosion.

Hepaidtheboy$10forwashingtenwindows,mostof____hadn'tbeencleanedforatleastayear.