Most volunteers are from universities, _________ it is not uncommon to see middle and primary school students too.
| A．though | B．however | C．since | D．even if |
Two explosions near the finish line of the Boston Marathon killed at least 3 people and injured more than 180 others, and currently FBI has figured out how it __________.
| A．came up | B．came out | C．came across | D．came about |
A person ________ with H7N9 viruses will be more likely to die of lung dysfunction.
| A．developed | B．infected | C．injected | D．progressed |
The children talked so loudly at dinner table that I had to struggle _________
| A．to be heard | B．to have heard | C．hearing | D．being heard |
At present, computer knowledge has become ___________ requirement as the ability to read and write.
| A．so basic a | B．so a basic | C．as basic a | D．as a basic |
Make sure the gas is turned off after a bath, which would ________ cause danger.
| A．somehow | B．meanwhile | C．otherwise | D．furthermore |