168. Whenever I met him, _____ was fairly frequent, _____ I liked his sweet and hopeful smile.
The _____ of electricity added to our difficulty repairing the bridge.
After her son died in a car accident, the old lady would sit at the window, ______ out and _______ in thought.
.I found some old pictures at the back of my drawer which _____ memories of my childhood.
I like the colour of the cap ______ I dislike its design.
It is believed that _____ European scientist invented _______.