I shall never forget the day _________Shen Zhou V was launched,_________has a great effect on my life.
| A．when;which | B．that;which | C．which;that | D．when;that |
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If I ___________ you would drop in, I would have stayed home waiting for you.
| A．have known | B．knew | C．would know | D．had known |
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—When will you be back, Peter?
—___________ a couple of days.
| A．On | B．In | C．For | D．By |
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. All books ___________ to the library more than three days late will be subject to a fine.
| A．return | B．returning | C．to return | D．returned |
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When he was only thirty years old, he had already experienced ___________ most people only experience when they are much older.
| A．what | B．which | C．who | D．when |
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___________ in the sports world, a sportsman needs to train constantly to keep himself in best condition.
| A．Survive | B．Surviving | C．To survive | D．Survived |