When _________ help, one often says “Thank you．” or “It’s kind of you．”

offering

to offer

to be offered

offered

How much would you _________ for repairing my bike?

pay

take

cost

charge

David said that it was because of his strong interest in literature _________ he chose the course．

that

what

why

how

Unwrapping the package Della said Jim _________ the watch, of which they were both proud．

ought not to sell

wouldn’t have sold

can’t have sold

shouldn’t have sold

The physics teacher said the earth _________ around the sun．

is moving

moved

had moved

moves

Granny Lan once told us she _________ a lot during World War Ⅱ, _________ her husband and children．

had suffered; lost

suffered; losing

had suffered; losing

had suffered; had lost

The physics teacher once said that we first _________ the lightning followed by thunders because light _________ faster than sound．

see; travelled

saw; travelled

saw; travels

see; travels

Without anyone _________, he slipped through the window．

noticing

noticed

to notice

being noticed

In the reading room, we found her _________ at a desk, with her attention _________ on a book．

sitting; fixing

to sit; fixed

seating; fixing

seated; fixed

Generally speaking, if _________ according to the instructions, the electric-bike is not as dangerous as reported．

riding

ridden

to ride

to be ridden