There are a great number of natural resources in the desert, which remain to be ________.
| A．explored | B．exploited |
| C．exploded | D．exposed |
---Why was it ______ you were so angry？
---Because we failed to take part in the basketball match.
| A．which | B．that | C．how | D．when |
The Bakers intend to buy a house but _____ must be within their power.
| A．they | B．one | C．it | D．which |
Fully ______in preparing teaching assignment at school，she no longer has much time to enjoy the various activities as usual.
| A．occupy | B．occupying |
| C．occupied | D．to occupy |
---Where is your report of this month？
---Oh sorry，I______ to email to you.
| A．forget | B．have forgotten |
| C．forgot | D．was forgetting |
She is always the first staff to go to the office and the last to leave，______ I guess is why she is promoted so quickly.
| A．who | B．which | C．that | D．what |