I wrote him a letter to show my ________ of his thoughtfulness.
| A．consequence | B．potential | C．instruction | D．appreciation. |
Canada's economic wealth is closely linked to _______ of the US, which buys three-quarters of its exports.
| A．which | B．what | C．that | D．one |
Thanks to your help, ________ I would not have completed the task on time.
| A．however | B．because | C．so | D．otherwise |
The conflict had developed into a stage ______ the two countries were gathering big troops on the border.
| A．where | B．when | C．which | D．that |
The schools themselves admit that not all children will be successful in the jobs ______ they are being trained.
| A．in that | B．for that | C．in which | D．for which |
______ scientists know where a storm will happen, winds will suddenly change, carrying the storm to a new direction.
| A．Even if | B．Since | C．Despite | D．Unless |